You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
Export thread
HELP Please...it caught fire
#1
I
inline300
I
inline300
I have a murray with a 12.5hp briggs and stratton I/C gold
I was given a mower for free, Id seen it sit in my neighbors yard for about two years now. Visually, the mower looks new. They even covered the engine.
They moved out and told me I could have it.
What I do know and have done.
Checked battery voltage. Zero.
Put air in the tires.
I jumped the mower with my other mower, it fired right up. Awesome.
Few minutes later I notice the engine begin to smoke a little.
So I pop the filter cover off and notice oil in the filter housing.
I left the cover off and fired the mower up again, and oil spewed out of the breather hose like water through a hose. Turn it off.
I check the oil, to me, it seemed the oil was over filled, excessively. so I drain it, and put in the required amount.
Fire the mower back up, it smokes but I figure this is just oil that has accumulated from an overfilled of oil. It eventually burns off and runs fine for about twenty minutes, I go to mow with it a little and all of a sudden the mower just stops moving forward, engine still ran at this point, I check into it, a pulley has destroyed itself, so I replace the pulley, fire the mower back up and proceed to mow.
All is well for ten minutes or so, then the engine begins to over rev, and a massive, thick, white cloud of smoke rolls out of the exhaust, engine boggs down.
I attribute the problem to the over rev condition, causing the oil to puke from the breather tube. So I adjust the governor down, until the throttle blade is about 1/8" open when the throttle is fully engaged. This seems to take care of the overrevving. I go mow with it, left the hood up, filter off so I could keep an eye on the carb to see if any oil began to spew out excessively.
I mow for about ten minutes once again, all is well, then I see gas shoot out of the carb and well, a little fire happened. The choke lever melted and who knows what else.
When it first give me issue, I did a compression test and got right at 50 psi cold, I know in a big 4 stroke, thats way on the low side but I have no idea what a small engine compressin psi should read, I tried to find the info online but was unable too.
I know something about big 4 stroke engines but this is the first time Ive tried to even tackle a small 4 stroke, seems they a slightly different animal.
Guess Im looking for direction. Why would oil gush out the breather hole? Why would gas have squirt out of the carb inlet?
Despite the bad, the mower cut good when it cut, everything else looks good, minimal almost nonexistant rust on the sheetmetal, paint is still shiny and new looking, seat is damaged, as the mower sat out in the weather for a couple years but it seems like it has potential.
I have no idea what a used good, or new briggs 12.5hp gold motor would run to replace or what it might cost to rebuild this one?
Any input appreciated, alot to read I know but I tried to put it all out there.
Thanks
I was given a mower for free, Id seen it sit in my neighbors yard for about two years now. Visually, the mower looks new. They even covered the engine.
They moved out and told me I could have it.
What I do know and have done.
Checked battery voltage. Zero.
Put air in the tires.
I jumped the mower with my other mower, it fired right up. Awesome.
Few minutes later I notice the engine begin to smoke a little.
So I pop the filter cover off and notice oil in the filter housing.
I left the cover off and fired the mower up again, and oil spewed out of the breather hose like water through a hose. Turn it off.
I check the oil, to me, it seemed the oil was over filled, excessively. so I drain it, and put in the required amount.
Fire the mower back up, it smokes but I figure this is just oil that has accumulated from an overfilled of oil. It eventually burns off and runs fine for about twenty minutes, I go to mow with it a little and all of a sudden the mower just stops moving forward, engine still ran at this point, I check into it, a pulley has destroyed itself, so I replace the pulley, fire the mower back up and proceed to mow.
All is well for ten minutes or so, then the engine begins to over rev, and a massive, thick, white cloud of smoke rolls out of the exhaust, engine boggs down.
I attribute the problem to the over rev condition, causing the oil to puke from the breather tube. So I adjust the governor down, until the throttle blade is about 1/8" open when the throttle is fully engaged. This seems to take care of the overrevving. I go mow with it, left the hood up, filter off so I could keep an eye on the carb to see if any oil began to spew out excessively.
I mow for about ten minutes once again, all is well, then I see gas shoot out of the carb and well, a little fire happened. The choke lever melted and who knows what else.
When it first give me issue, I did a compression test and got right at 50 psi cold, I know in a big 4 stroke, thats way on the low side but I have no idea what a small engine compressin psi should read, I tried to find the info online but was unable too.
I know something about big 4 stroke engines but this is the first time Ive tried to even tackle a small 4 stroke, seems they a slightly different animal.
Guess Im looking for direction. Why would oil gush out the breather hole? Why would gas have squirt out of the carb inlet?
Despite the bad, the mower cut good when it cut, everything else looks good, minimal almost nonexistant rust on the sheetmetal, paint is still shiny and new looking, seat is damaged, as the mower sat out in the weather for a couple years but it seems like it has potential.
I have no idea what a used good, or new briggs 12.5hp gold motor would run to replace or what it might cost to rebuild this one?
Any input appreciated, alot to read I know but I tried to put it all out there.
Thanks
#2
K
KennyV
K
KennyV
Hello and welcome to the group...
It sounds like you don't have too much invested in this mower so it is definitely worth fixing ...:wink:
The over full oil leads me to think you are getting raw fuel into the crank case, and then the crank is splashing it around and out the vent tube into the intake path.
Since the engine will run good for a while I'm going to figure that the rings are not badly damaged (yet)...
You have a carburetor problem allowing a lot of fuel (not just running too rich) ... You may also have an intake leak, air plus too much fuel = run away RPM...
You are definitely going to need some carb parts and might need a complete carburetor (fire is sometimes unforgiving)...
inline300 ... Ford? ... :smile:KennyV
It sounds like you don't have too much invested in this mower so it is definitely worth fixing ...:wink:
The over full oil leads me to think you are getting raw fuel into the crank case, and then the crank is splashing it around and out the vent tube into the intake path.
Since the engine will run good for a while I'm going to figure that the rings are not badly damaged (yet)...
You have a carburetor problem allowing a lot of fuel (not just running too rich) ... You may also have an intake leak, air plus too much fuel = run away RPM...
You are definitely going to need some carb parts and might need a complete carburetor (fire is sometimes unforgiving)...
inline300 ... Ford? ... :smile:KennyV
#3
I
inline300
I
inline300
I just would not have thought of that, makes alot of sense.
I did check the oil level after this happened to see just how much oil was shot out the breather tube and did think the oil level was again unusually high.
I wasnt sure if there might be some oil passage blocked, causing a false reading at the dipstick, as I just have no idea about the internals of this engine but gas in the oil makes sense.
Is there a reputable online source for parts? Local guy is nice and all but he comes with a 30% mark up, as compared to online prices. :laughing:
Yep, my username does refer to the old ford inline engine. :biggrin:
Thanks man, much appreciated.
I did check the oil level after this happened to see just how much oil was shot out the breather tube and did think the oil level was again unusually high.
I wasnt sure if there might be some oil passage blocked, causing a false reading at the dipstick, as I just have no idea about the internals of this engine but gas in the oil makes sense.
Is there a reputable online source for parts? Local guy is nice and all but he comes with a 30% mark up, as compared to online prices. :laughing:
Yep, my username does refer to the old ford inline engine. :biggrin:
Thanks man, much appreciated.
#4
RobertBrown
RobertBrown
http://www.lawnmowerforum.com/small-engine-mower-repair/755-fuel-line-string-trimmer.html
There's a couple of souces mentioned in this thread.
Sorry about your bad luck...so much for free mowers eh?
#5
K
KennyV
K
KennyV
This is a good site to find tear down rebuild info on small engine carbs.. scroll down till you see your carb ..
Small Engine Equipment Troubleshooting, Repairs and Safety
This is one source for parts and parts breakdown identification there are several others...
Lawn Mower Parts
Can't beat free mowers... If nothing else they are a great source for parts, and often something rather simple will put it back into service...
Ford 300's were VERY good engines... :smile:KennyV
Small Engine Equipment Troubleshooting, Repairs and Safety
This is one source for parts and parts breakdown identification there are several others...
Lawn Mower Parts
Can't beat free mowers... If nothing else they are a great source for parts, and often something rather simple will put it back into service...
Ford 300's were VERY good engines... :smile:KennyV
#6
I
inline300
I
inline300
Ah, I still think it was good luck. This old mower cuts and looks suprisingly good, I wouldnt hesitate to just drop a new motor in it.
They give me a push mower, said they couldnt get it to run, I messed around with it, mowed part of my yard with it earlier, so I cannot complain.
Appreciate the links Robert and Kenny, Ill check those links out.
Inline 300's are still good engines, if you can get past the fact new engines make over 400hp in trucks, gobbs of torque and just as reliable with better fuel economy...
They give me a push mower, said they couldnt get it to run, I messed around with it, mowed part of my yard with it earlier, so I cannot complain.
Appreciate the links Robert and Kenny, Ill check those links out.
Inline 300's are still good engines, if you can get past the fact new engines make over 400hp in trucks, gobbs of torque and just as reliable with better fuel economy...
#7
B
Bethieboo
B
Bethieboo
Wow, I would probably panic and freak out if my mower caught fire! If you can drop a new engine in to it then why not. It sounds like you can get many more years out of it once you have it fixed. Keep us posted and be careful... just in case!
#8
dria
dria
Bethie, might I suggest that you get yourself a few fire extinguishers and practice using them. Once you have done this you might not feel so freaked out about fire.
#9
D
DakotaMM
D
DakotaMM
Dria you make a good point. I have a lot of fire extinguishers around here but I have never practiced using one. If an emergency broke out I would have to stop and read the instructions! Thanks for the idea.
#10
JDgreen
Why do you even have fire extinguishers if you don't know how to use them !!!!!???? :confused2:
Just pull the pin, point it at the base of the fire from about ten feet away, and squeeze the handles together. This assumes they are still charged and if they are the dry chemical type, the powder has not caked in the bottom and they do not work. Twice a year I check all my extinguishers for pressure using the gage, then turn them upside down and whack the base with a big plastic mallet a few times. And when I buy a new one, I write the date on the bottom with a big black marker and when they are ten years old, I replace the unit itself. Have the extinguishers in every building here on every floor, multiple units in the house, in every vehicle, even on my tractor, have never needed one BUT:
BETTER TO HAVE ONE AND NOT NEED IT, THAN NEED ONE AND NOT HAVE IT. :thumbsup:
JDgreen
Dria you make a good point. I have a lot of fire extinguishers around here but I have never practiced using one. If an emergency broke out I would have to stop and read the instructions! Thanks for the idea.
Why do you even have fire extinguishers if you don't know how to use them !!!!!???? :confused2:
Just pull the pin, point it at the base of the fire from about ten feet away, and squeeze the handles together. This assumes they are still charged and if they are the dry chemical type, the powder has not caked in the bottom and they do not work. Twice a year I check all my extinguishers for pressure using the gage, then turn them upside down and whack the base with a big plastic mallet a few times. And when I buy a new one, I write the date on the bottom with a big black marker and when they are ten years old, I replace the unit itself. Have the extinguishers in every building here on every floor, multiple units in the house, in every vehicle, even on my tractor, have never needed one BUT:
BETTER TO HAVE ONE AND NOT NEED IT, THAN NEED ONE AND NOT HAVE IT. :thumbsup:
#11
JDgreen
Oh yeah...have a '90 F-150 with the inline 300 with FI, tow rating was 5000 lbs, put on a Flowmaster exhaust system and it would pull 7000 easily, best engine Ford every made.
JDgreen
Ah, I still think it was good luck. This old mower cuts and looks suprisingly good, I wouldnt hesitate to just drop a new motor in it.
They give me a push mower, said they couldnt get it to run, I messed around with it, mowed part of my yard with it earlier, so I cannot complain.
Appreciate the links Robert and Kenny, Ill check those links out.
Inline 300's are still good engines, if you can get past the fact new engines make over 400hp in trucks, gobbs of torque and just as reliable with better fuel economy...
Oh yeah...have a '90 F-150 with the inline 300 with FI, tow rating was 5000 lbs, put on a Flowmaster exhaust system and it would pull 7000 easily, best engine Ford every made.
#12
I
inline300
I
inline300
Ive had a couple trucks with the 4.9 engine. The 95 model I have now, I put headers on it, freed up the exhaust, electric fan. Seems to pull a tad better. Had it for 13yrs now, still putts along like it did when I got it. The 4.9 engine makes no sense in a truck until you tow with it, then it seens to come alive and make perfect sense. haha
Little update on the mower situation.
Still revs way too high and adjusting the throttle down via the throttle lever does nothing to slow it down. It does seem like a air leak or vac leak, whatever its referred too on small engines.
This is what I do know.
Engine still has compression.
Oil level appears normal.
Carb is fine, I took it appart, cleaned it. The plastic piece that holds the choke blade melted off due to the fire but I removed the choke blade, so thats not an issue. Right now Im using two fingers as a manual choke, until I can figure out whats causing the over rev condition, once thats figured out, Ill fix the choke blade.
I checked the intake to carb gasket, there are no cracks or breaks. I replaced the intake to cylinder head gasket.
This is what I noticed and am not sure what the correct setting(s), should be, maybe someone can fill me in.
With the throttle lever in the slowest position, the throttle blade is still 3/16 or so open, to me that seems excessive. There is a throttle stop on the top of the carb, if I close the throttle blade until the hinge makes contact with this stop, the engine dies. With the way this thing revs up hard youd think it would have a massive air leak somewhere, so the fact the engine dies when the throttle blade is closed kinda puzzled me, Id expect it to bog down and then die but it just flat dies. As mentioned, with the throttle lever in the slowest position, the throttle blade is still 3/16" open. From this point to wide open, the engine seemingly runs wide open. If I manually close the throttle blade from the 3/16" position until it hits the throttle stop, I can get the engine to gradually wind down, or decrease the rpms in a linear manner until it dies. But from the 3/16" or lowest throttle lever setting, to full throttle setting/ throttle blade wide open, the rpms seem to be the same, which to me suggests a huge air leak somewhere.
I dont know what the head gasket or internal passages look like, so I have no idea if a blown headgasket would cause this issue, the cylinder psi cold was 50 psi and again, I dont know if thats considered normal or extremely low? If its low, then I might think its the head gasket.
Another thing Im not clear on, is if I let this thing run at the rpms its running (excessive) for say ten twenty seconds, oil shoots out the breather tube. Which tells me pressure is building up in the crankcase or whatever you call it on a small engine, which kinda suggests to me it could possibly be a blown head gasket. Maybe not, as again, I dont know how these things work internally, so perhaps if it has an oil pump, then excessive rpms and oil shooting out the breather might be normal but if the oil circulates via another method, then Id have to lean back to excessive pressure inside the crankcase or blown head gasket.
I may very well be over thinking it all, so any input appreciated. Right now Im just guessing.
Im fairly certain the fuel side or carb is fine, hell, it has a little carb like the atc70 I redid, not alot going on inside there. The float inside the carb is fine, I checked its buoyancy.
Again, any input appreciated, and yes, I had my fire extinguisher on hand. :biggrin:
Little update on the mower situation.
Still revs way too high and adjusting the throttle down via the throttle lever does nothing to slow it down. It does seem like a air leak or vac leak, whatever its referred too on small engines.
This is what I do know.
Engine still has compression.
Oil level appears normal.
Carb is fine, I took it appart, cleaned it. The plastic piece that holds the choke blade melted off due to the fire but I removed the choke blade, so thats not an issue. Right now Im using two fingers as a manual choke, until I can figure out whats causing the over rev condition, once thats figured out, Ill fix the choke blade.
I checked the intake to carb gasket, there are no cracks or breaks. I replaced the intake to cylinder head gasket.
This is what I noticed and am not sure what the correct setting(s), should be, maybe someone can fill me in.
With the throttle lever in the slowest position, the throttle blade is still 3/16 or so open, to me that seems excessive. There is a throttle stop on the top of the carb, if I close the throttle blade until the hinge makes contact with this stop, the engine dies. With the way this thing revs up hard youd think it would have a massive air leak somewhere, so the fact the engine dies when the throttle blade is closed kinda puzzled me, Id expect it to bog down and then die but it just flat dies. As mentioned, with the throttle lever in the slowest position, the throttle blade is still 3/16" open. From this point to wide open, the engine seemingly runs wide open. If I manually close the throttle blade from the 3/16" position until it hits the throttle stop, I can get the engine to gradually wind down, or decrease the rpms in a linear manner until it dies. But from the 3/16" or lowest throttle lever setting, to full throttle setting/ throttle blade wide open, the rpms seem to be the same, which to me suggests a huge air leak somewhere.
I dont know what the head gasket or internal passages look like, so I have no idea if a blown headgasket would cause this issue, the cylinder psi cold was 50 psi and again, I dont know if thats considered normal or extremely low? If its low, then I might think its the head gasket.
Another thing Im not clear on, is if I let this thing run at the rpms its running (excessive) for say ten twenty seconds, oil shoots out the breather tube. Which tells me pressure is building up in the crankcase or whatever you call it on a small engine, which kinda suggests to me it could possibly be a blown head gasket. Maybe not, as again, I dont know how these things work internally, so perhaps if it has an oil pump, then excessive rpms and oil shooting out the breather might be normal but if the oil circulates via another method, then Id have to lean back to excessive pressure inside the crankcase or blown head gasket.
I may very well be over thinking it all, so any input appreciated. Right now Im just guessing.
Im fairly certain the fuel side or carb is fine, hell, it has a little carb like the atc70 I redid, not alot going on inside there. The float inside the carb is fine, I checked its buoyancy.
Again, any input appreciated, and yes, I had my fire extinguisher on hand. :biggrin:
#13
twocycletim
twocycletim
I would suggest cleaning the carb, and while doing so inspect the needle valve. a piece of trash could be keeping the needle valve open, or the valve could be worn out. I had the same problem with a 12.5 hp kawasaki on a toro walk behind, cleaning the carb fixed it!:thumbsup:
#15
twocycletim
twocycletim
50psi is too low should be 90 or better, your probably on the right track with the head gasket. Have you tried spraying the mating surfaces with carb cleaner while it is running, to see if the engine changes tempo?
#17
I
inline300
I
inline300
Think it is the head gasket.
I dropped the bowl on the carb to double check the float and needle/seat, and it was definitely stopping the gas flow, so it works fine.
Took the engine cover off and noticed a dark spot on the cylinder gasket.
Rigged the engine so it would run and run at a low rpm.
All I had on hand was wd40, so I sprayed the spot and definitely noticed movement, meaning air is escaping, I dont think thats the cause of the problem but I think it, at least in my amatuer opinion, would suggest the cylinder gasket has potentially failed elsewhere, if not related too this leak, not visible to the naked eye.
It kinda makes sense to me, cause if a headgasket blew on a big 4 stroke engine, youd see unusual things happen as fluid spewed out in peculiar places, so I would rekon the same would apply to the small 4 stroke. :biggrin:
Open to thoughts. Like I say, I dont know what in the hell the internals look like on the small 4 stroke or what is reasonable to expect, have dial up, so watching the available online videos isnt an option.
Thanks
I dropped the bowl on the carb to double check the float and needle/seat, and it was definitely stopping the gas flow, so it works fine.
Took the engine cover off and noticed a dark spot on the cylinder gasket.
Rigged the engine so it would run and run at a low rpm.
All I had on hand was wd40, so I sprayed the spot and definitely noticed movement, meaning air is escaping, I dont think thats the cause of the problem but I think it, at least in my amatuer opinion, would suggest the cylinder gasket has potentially failed elsewhere, if not related too this leak, not visible to the naked eye.
It kinda makes sense to me, cause if a headgasket blew on a big 4 stroke engine, youd see unusual things happen as fluid spewed out in peculiar places, so I would rekon the same would apply to the small 4 stroke. :biggrin:
Open to thoughts. Like I say, I dont know what in the hell the internals look like on the small 4 stroke or what is reasonable to expect, have dial up, so watching the available online videos isnt an option.
Thanks
#18
I
inline300
I
inline300
Im guessing yes but the head bolts are torque to yield correct?
Anyone have or know where to find the torque specs?
So far I removed the head cover, or whatever you want to call it. The gasket seemed fine, except at the bottom left, there was a bit of oil, seems the cylinder/piston was drawing in some oil through the bolt hole.
I also noticed the head bolts were extremely easy to remove, so Im thinking that may have been part of the problem too.
We shall see.
Once I get some carb gaskets, new intake and head gasket, Ill know more I guess, running out of possibilities.
Theres really nothing to these things, after I get a look at it.
I noticed alotta casting flash inside the exh and int ports, makes a perfectionist fella wanna break out the grinder.:biggrin:
Thanks folks.
Anyone have or know where to find the torque specs?
So far I removed the head cover, or whatever you want to call it. The gasket seemed fine, except at the bottom left, there was a bit of oil, seems the cylinder/piston was drawing in some oil through the bolt hole.
I also noticed the head bolts were extremely easy to remove, so Im thinking that may have been part of the problem too.
We shall see.
Once I get some carb gaskets, new intake and head gasket, Ill know more I guess, running out of possibilities.
Theres really nothing to these things, after I get a look at it.
I noticed alotta casting flash inside the exh and int ports, makes a perfectionist fella wanna break out the grinder.:biggrin:
Thanks folks.
#19
K
KennyV
You can find all your torque specs here... Small Engine Specifications Index
Porting and polishing is something that helps engines toward the big end, you are not going to put those kind of RPM on this engine... I hope:biggrin:....
If you do that don't get too carried away, I would just leave it and consider the the obstructions as turbulence inducing mixing refinements :laughing:...
Take the head off and see what you find... I like Copper Cote spray, don't know that it's necessary but I have always used it on head-gaskets... :smile:KennyV
K
KennyV
Anyone have or know where to find the torque specs?
I noticed alotta casting flash inside the exh and int ports, makes a perfectionist fella wanna break out the grinder.:biggrin:
Thanks folks.
You can find all your torque specs here... Small Engine Specifications Index
Porting and polishing is something that helps engines toward the big end, you are not going to put those kind of RPM on this engine... I hope:biggrin:....
If you do that don't get too carried away, I would just leave it and consider the the obstructions as turbulence inducing mixing refinements :laughing:...
Take the head off and see what you find... I like Copper Cote spray, don't know that it's necessary but I have always used it on head-gaskets... :smile:KennyV
#20
briggs
briggs
to me it sounds like head gasket ... ..I would also check the valves to make sure they are closing properly ...also have a look at your flywheel key if its off set a little this would cause a fire in the carb ...Good luck and let us know how you make out
#21
I
inline300
I
inline300
Thanks kenny, Ill check out the link.
I was kidding about the port/polish...kinda. :biggrin:
I checked the valve movement, they seem to be seating very well. Ill double check that more closely when I install the head gasket. Good idea, thanks.
I was kidding about the port/polish...kinda. :biggrin:
I checked the valve movement, they seem to be seating very well. Ill double check that more closely when I install the head gasket. Good idea, thanks.
#22
I
inline300
I
inline300
Update. Still revs way too high at all throttle positions.
This is what I know.
Carb is clean, fuel is new. float/needle/seat work as you would expect.
Intake gaskets new.
Head gasket new.
Valves were seating just fine.
Oil level is normal.
If I start the engine, and hold the throttle blade closed, the engine rpms will go low like you would expect and run at a low rpm almost die out, however, if you open the throttle just a hair bit more, the rpm of the engine climbs to an excessive level. You can have the throttle lever set on slow or fast and it makes no difference.
Im not clear what the engine governor is supposed to do, I know limit rpm, but in what way? As wide open throttle is wide open throttle, how would the governor limit rpm? I read a method to adjust the governor. I loosened the arm from the shaft, set the engine throttle to wide open but before the choke would close, took a screwdriver, turned the governor shaft clockwise, then tightened the governor arm down. This made no significant change.
Right now Im at a loss, have to do some more reading but if anyone has a suggestion, throw it my way.
Thanks
This is what I know.
Carb is clean, fuel is new. float/needle/seat work as you would expect.
Intake gaskets new.
Head gasket new.
Valves were seating just fine.
Oil level is normal.
If I start the engine, and hold the throttle blade closed, the engine rpms will go low like you would expect and run at a low rpm almost die out, however, if you open the throttle just a hair bit more, the rpm of the engine climbs to an excessive level. You can have the throttle lever set on slow or fast and it makes no difference.
Im not clear what the engine governor is supposed to do, I know limit rpm, but in what way? As wide open throttle is wide open throttle, how would the governor limit rpm? I read a method to adjust the governor. I loosened the arm from the shaft, set the engine throttle to wide open but before the choke would close, took a screwdriver, turned the governor shaft clockwise, then tightened the governor arm down. This made no significant change.
Right now Im at a loss, have to do some more reading but if anyone has a suggestion, throw it my way.
Thanks
#23
K
KennyV
K
KennyV
Here is a quick link for setting the governor...
Understanding and Adjusting your Governor on a small engine
and here is a youtube video
YouTube - Briggs and Stratton Governor set up and adjustment
this is on a typical set up...
If the governor is not able to control the RPM with the linkage to the carb... I'm wondering if you have the right carb on the engine? Someone may have changed the carb &/or the linkage ??
Keep at it ... you will eventually find what is causing these problems... :smile:KennyV
Understanding and Adjusting your Governor on a small engine
and here is a youtube video
YouTube - Briggs and Stratton Governor set up and adjustment
this is on a typical set up...
If the governor is not able to control the RPM with the linkage to the carb... I'm wondering if you have the right carb on the engine? Someone may have changed the carb &/or the linkage ??
Keep at it ... you will eventually find what is causing these problems... :smile:KennyV
#24
briggs
briggs
this has me baffled ..I did see this on a Tecumseh engine once it turned out to be the carb it self ..The throttle shaft had enough slop in it to suck air and cause it to over rev ...I dont have my book here with me or i would go threw it and see what i could find... truly a brain teaser here
#25
I
inline300
I
inline300
Its the oem carb, it seems to match the photos Ive found for the engine. Think I need some help double checking the linkage though.
On small 4 stroke engines, the carb throttle blade should be fully closed in the slowest position, correct?
The throttle blade should be fully open in the fastest position?
On small 4 stroke engines, the carb throttle blade should be fully closed in the slowest position, correct?
The throttle blade should be fully open in the fastest position?
#26
briggs
briggs
can you post a pic for me i would like to see the carb .....
#27
RobertBrown
RobertBrown
good thing you didn't put it in your garage before it caught fire.Ah, I still think it was good luck. This old mower cuts and looks suprisingly good, I wouldnt hesitate to just drop a new motor in it.
#28
I
inline300
I
inline300
Photos with captions/ questions.
All the parts are stock, including the carb, I verified it at partstree dot com
briggs&stratton 286707-0437-01
Keep in mind, the choke is missing.
on a side note, parts tree wants 35 dang dollars for a choke shaft, holy crap. I could pay a machinist to make one for less or hand craft one from a piece of stock with a file. lol
All the parts are stock, including the carb, I verified it at partstree dot com
briggs&stratton 286707-0437-01
Keep in mind, the choke is missing.
on a side note, parts tree wants 35 dang dollars for a choke shaft, holy crap. I could pay a machinist to make one for less or hand craft one from a piece of stock with a file. lol
Attachments
#29
briggs
briggs
how far is this screw in it sets the position of your throttle and gov also ..if its screwed in to far it will rev high..The spring is on the linkage it looks good .I would also look at the throttle cable to make sure its set proper so it can open and close all the way ..I have the same carb on my 12hp I/C brigs ..I wont be at my shop till thur i ..If you dont have it fixed by then i will send you pics of mine and send you the info right out my shop manual
Attachments
#30
I
inline300
I
inline300
I made some progress today, kinda having what you have in mind Briggs, I starred and starred some more at the linkage and I finally realized, someone had bent the linkage stop back, not giving it full travel, so slow was more like part to mid throttle.
So the good news, the throttle linkage is squared away, and it will idle reasonably low.
The bad news, the idle is kinda higher than expected and once you crack the throttle open to a hair below part throttle, the engine wants to rev itself to death. So and fast speeds are accomplished with about 1/2" movement of the throttle lever, as opposed to the 2" potential travel of the speed lever.
Out of curiosity, I turned the airscrew all the way in while it was idling, this shoulda killed it but it kept running.
This makes me think air leak somewhere, so the best I know to do right now, is to start over, Im gonna tear the carb apart, clean, soak, blow air, perform ritual dances and give it the royal treatment and replace every thing thats not made of metal between the cylinder head and airfilter. :biggrin
Sound good?
And just so Im 100% sure, if the throttle lever is set to the fastest speed, the carb butterfly should be fully open or no? Im thinking no, as I believe the governor is meant to increase the engine speed by opening the throttle, if the engine is put under load, say cutting tall grass all of a sudden, so Im thinking if the throttle is open all the way under the fast lever setting, then the governor cant open the throttle any more? Thoughts?
Have another question, just a general mower question, the mower I have been using, has a 18 hp briggs v-twin engine, any chance the 12.5 and 18hp would use the same mounting points/drive gears? Cause I wouldnt be opposed to doing an engine swap. :biggrin: Funny thing is, the neighbor on the other side of me give that mower to me, he thought the transaxle was fried, but I replaced some belts and have been using it ever since, its an old one but it runs pretty good.
So the good news, the throttle linkage is squared away, and it will idle reasonably low.
The bad news, the idle is kinda higher than expected and once you crack the throttle open to a hair below part throttle, the engine wants to rev itself to death. So and fast speeds are accomplished with about 1/2" movement of the throttle lever, as opposed to the 2" potential travel of the speed lever.
Out of curiosity, I turned the airscrew all the way in while it was idling, this shoulda killed it but it kept running.
This makes me think air leak somewhere, so the best I know to do right now, is to start over, Im gonna tear the carb apart, clean, soak, blow air, perform ritual dances and give it the royal treatment and replace every thing thats not made of metal between the cylinder head and airfilter. :biggrin
Sound good?
And just so Im 100% sure, if the throttle lever is set to the fastest speed, the carb butterfly should be fully open or no? Im thinking no, as I believe the governor is meant to increase the engine speed by opening the throttle, if the engine is put under load, say cutting tall grass all of a sudden, so Im thinking if the throttle is open all the way under the fast lever setting, then the governor cant open the throttle any more? Thoughts?
Have another question, just a general mower question, the mower I have been using, has a 18 hp briggs v-twin engine, any chance the 12.5 and 18hp would use the same mounting points/drive gears? Cause I wouldnt be opposed to doing an engine swap. :biggrin: Funny thing is, the neighbor on the other side of me give that mower to me, he thought the transaxle was fried, but I replaced some belts and have been using it ever since, its an old one but it runs pretty good.
#31
K
KennyV
Have you felt resistance on the governor arm with the engine running... Is the governor actually working?
Have you taken the screw and it's seat completely out to check if the point is damaged?
You can easily swap engines but this one needs to be figured out... too strange. :smile:KennyV
K
KennyV
The bad news, the idle is kinda higher than expected and once you crack the throttle opne a hair bit more, the engine wants to rev itself to death.
Out of curiosity, I turned the airscrew all the way in while it was idling, this shoulda killed it but it kept running.
Have you felt resistance on the governor arm with the engine running... Is the governor actually working?
Have you taken the screw and it's seat completely out to check if the point is damaged?
You can easily swap engines but this one needs to be figured out... too strange. :smile:KennyV
#32
I
inline300
I
inline300
I would say there was some resistance with the governor arm when it was running. Governor moves freely when not running.
Air screw tip was fine.
Should the carb butterfly open fully when the throttle control lever is set to FAST?
Air screw tip was fine.
Should the carb butterfly open fully when the throttle control lever is set to FAST?
#33
K
KennyV
Yes is your linkage allowing it to fully open?
K
KennyV
Should the carb butterfly open fully when the throttle control lever is set to FAST?
Yes is your linkage allowing it to fully open?
#34
I
inline300
I
inline300
I know it seemed like a basic question but I had to ask.
Yes, linkage works fine now.
Im still at a loss. Gonna put a new governor spring on it while Im throwing money at it.
Yes, linkage works fine now.
Im still at a loss. Gonna put a new governor spring on it while Im throwing money at it.
#35
J
jhwentworth
Small engine governors work by limiting engine RPMs. If you removed the governor's connection to the throttle platem and had the throttle level full on, the motor would rev very high, for a while. The throttle lever is trying to open the throttle plate and the governor is trying to prevent that. The higher the engine RPMs the more force the governor applies to counteract the pressure from the throttle lever.
When you open the throttle lever with the engine not running the throttle plate should be wide open. After the engine starts and increases RPM the governor should start to move to limit the speed. If you move the governor can you limit engine speed? Is the governor moving with engine speed changes? The internals of the governor do break, and the symptoms would be what you're seeing.
The problem you found with the idle screw cranked in is quite common. People use the idle adjustment to cover up a problem with low speed stalling or rough running.
J
jhwentworth
And just so Im 100% sure, if the throttle lever is set to the fastest speed, the carb butterfly should be fully open or no? Im thinking no, as I believe the governor is meant to increase the engine speed by opening the throttle, if the engine is put under load, say cutting tall grass all of a sudden, so Im thinking if the throttle is open all the way under the fast lever setting, then the governor cant open the throttle any more? Thoughts?
.
Small engine governors work by limiting engine RPMs. If you removed the governor's connection to the throttle platem and had the throttle level full on, the motor would rev very high, for a while. The throttle lever is trying to open the throttle plate and the governor is trying to prevent that. The higher the engine RPMs the more force the governor applies to counteract the pressure from the throttle lever.
When you open the throttle lever with the engine not running the throttle plate should be wide open. After the engine starts and increases RPM the governor should start to move to limit the speed. If you move the governor can you limit engine speed? Is the governor moving with engine speed changes? The internals of the governor do break, and the symptoms would be what you're seeing.
The problem you found with the idle screw cranked in is quite common. People use the idle adjustment to cover up a problem with low speed stalling or rough running.
#36
I
inline300
I
inline300
Gotta love troubleshooting
I just went out, fired the mower up, this is what I experienced.
Engine NOT running.
Governor arm moves freely back and forth.
Engine RUNNING at IDLE.
I can physically move the governor arm with no resistance, and make the engine rev up and down. Otherwise, it idles fine, little on the high side but good, nothing unusual at this point.
Engine RUNNING at fastest position on the throttle lever.
Carb butterfly opens fully, Governor arm moves clockwise as far as it can, and at no point moves counter clockwise to slow down the engine.
Houston, I think we have a problem.:laughing:
Now my question is, is this a swap in and out type deal or will I need some special tool or information to replace? Could there be something else causing the governor itself not work?
What makes the governor work? When I look at the part diagram, it looks like a shaft with a canister hanging off it? Part #616
Parts and Diagrams for Briggs and Stratton 286707-0437-01
Thanks
I just went out, fired the mower up, this is what I experienced.
Engine NOT running.
Governor arm moves freely back and forth.
Engine RUNNING at IDLE.
I can physically move the governor arm with no resistance, and make the engine rev up and down. Otherwise, it idles fine, little on the high side but good, nothing unusual at this point.
Engine RUNNING at fastest position on the throttle lever.
Carb butterfly opens fully, Governor arm moves clockwise as far as it can, and at no point moves counter clockwise to slow down the engine.
Houston, I think we have a problem.:laughing:
Now my question is, is this a swap in and out type deal or will I need some special tool or information to replace? Could there be something else causing the governor itself not work?
What makes the governor work? When I look at the part diagram, it looks like a shaft with a canister hanging off it? Part #616
Parts and Diagrams for Briggs and Stratton 286707-0437-01
Thanks
#37
K
KennyV
Thats why I was asking about the governor showing resistance when the engine was running... If it isn't it is going to be internal, but an easy (sort of) fix... watch this youtube...
YouTube - how a governor works
I think you are on to a fix... :smile:KennyV
K
KennyV
Gotta love troubleshooting
Engine RUNNING at fastest position on the throttle lever.
Carb butterfly opens fully, Governor arm moves clockwise as far as it can, and at no point moves counter clockwise to slow down the engine.
What makes the governor work?
Thats why I was asking about the governor showing resistance when the engine was running... If it isn't it is going to be internal, but an easy (sort of) fix... watch this youtube...
YouTube - how a governor works
I think you are on to a fix... :smile:KennyV
#38
K
KennyV
K
KennyV
BTW it could be that arm #616 ... but most likely is the gear part that spins and pushes against the end of that arm...
You will need to take the end case off to see what is not right... Not really a terrible job. :thumbsup:
Take care not to score the main seal when you remove it, or you will end up with an oil leak...
:smile:KennyV
You will need to take the end case off to see what is not right... Not really a terrible job. :thumbsup:
Take care not to score the main seal when you remove it, or you will end up with an oil leak...
:smile:KennyV
#39
I
inline300
I
inline300
Well fellers, right after I clicked the submit button this morning, I decided instead of guess what na hell is inside these motors, Id just find out. :biggrin:
So maybe I took the flywheel off and realized I didnt have too but, now I know. haha
I finally realize how the governor works.
It also took about two seconds to realize why it wasnt working, the plastic gear is worn.
Guess Ill pick one of those up. I havent looked but surely to goodness they sell the gear without having to buy the other pieces.
Your right kenny, if I had understood what you were saying, I would have isolated the problem right away but I just had no idea. I should have asked for specifics but I didnt, I felt resistance clockwise due to the spring on the throttle linkage but what I didnt realize till this morning, is the resistance should be counter clockwise, forcing the throttle to close or lower.
Well folks, your help has been appreciated.
Thanks
So maybe I took the flywheel off and realized I didnt have too but, now I know. haha
I finally realize how the governor works.
It also took about two seconds to realize why it wasnt working, the plastic gear is worn.
Guess Ill pick one of those up. I havent looked but surely to goodness they sell the gear without having to buy the other pieces.
Your right kenny, if I had understood what you were saying, I would have isolated the problem right away but I just had no idea. I should have asked for specifics but I didnt, I felt resistance clockwise due to the spring on the throttle linkage but what I didnt realize till this morning, is the resistance should be counter clockwise, forcing the throttle to close or lower.
Well folks, your help has been appreciated.
Thanks
#40
briggs
briggs
this is how we all learn glad you found the prob ....let us know what happens
#41
I
inline300
I
inline300
Well fellas
Figured Id post what I learned, maybe someone one day can use the info to save theirself 35 bucks. :biggrin:
Earlier I mentioned the plastic shaft that holds the choke butterfly, melted. I got to looking at it, remembered someone give me a couple weedeaters, yeah I know, sounds odd. I remembered the choke and throttle shaft on the weedeaters were fairly long, considering the ports themselves are not big at all.
Long short, if you have the choke butterfly off the lawn mower carb, you can use the brass throttle shaft off the weedeater and the spring off the weedeater choke shaft, combined with a hacksaw, drill bit and about five minutes, to make what will appear to be an OE product. :biggrin:
Figured Id post what I learned, maybe someone one day can use the info to save theirself 35 bucks. :biggrin:
Earlier I mentioned the plastic shaft that holds the choke butterfly, melted. I got to looking at it, remembered someone give me a couple weedeaters, yeah I know, sounds odd. I remembered the choke and throttle shaft on the weedeaters were fairly long, considering the ports themselves are not big at all.
Long short, if you have the choke butterfly off the lawn mower carb, you can use the brass throttle shaft off the weedeater and the spring off the weedeater choke shaft, combined with a hacksaw, drill bit and about five minutes, to make what will appear to be an OE product. :biggrin:
#42
briggs
briggs
is the mower running now
#43
I
inline300
I
inline300
I was hoping someone would sell a replacement gear and not have to buy the entire assembly but apparently, they do not.
My way of saying, no I havent bought the parts yet but soon.
Ill let yall know how it does.
My way of saying, no I havent bought the parts yet but soon.
Ill let yall know how it does.
#44
I
inline300
I
inline300
Parts still havent arrived...imagine the shop will get them tomorrow.
I was able to get another push mower running.
Someone give me a yardman 6hp I think. It had sat in the rain for years, no air cleaner cover, so it was full of water.
Checked compression, zero. Took the head cover off, noticed the intake valve was seized. After much prying and wigglin and curse words, it came out, I cleaned it, stuck it back in, threw the head cover back on, I didnt even put a new gasket on it, changed the oil. It fired right up. :laughing:
I also got an old self propelled snapper mower, that thing was rotted and seized all over, think it was a 4hp engine, wonder if anyone would buy/need parts off the engine?
I was able to get another push mower running.
Someone give me a yardman 6hp I think. It had sat in the rain for years, no air cleaner cover, so it was full of water.
Checked compression, zero. Took the head cover off, noticed the intake valve was seized. After much prying and wigglin and curse words, it came out, I cleaned it, stuck it back in, threw the head cover back on, I didnt even put a new gasket on it, changed the oil. It fired right up. :laughing:
I also got an old self propelled snapper mower, that thing was rotted and seized all over, think it was a 4hp engine, wonder if anyone would buy/need parts off the engine?
#45
I
inline300
I
inline300
I have good news and bad news.
Good news:
Governor is in place. Engine fired right up. Everything looks clean and shiny and almost new. No oil shooting out the pvc box. :laughing::thumbsup:
Bad news:
Engine runs at a very very low rpm than youd expect.
If I remove the airfilter/cover (which is brand new), the rpms will increase to what I consider normal but still not quite as powerful as Id expect once the blades are engaged.
The little pvc box or whatever you wanna call it now vents directly to the atmosphere, I disconnected it from the air cleaner.
Sure enough though, if I remove the airfilter/cleaner, the rpms will shoot up, put it back on, they drop down, ya almost think its gonna die but it keeps on running.
Choke operates correctly, as does the throttle blade/linkage.
I adjusted the governor best I know how, by setting the throttle lever to fast, making sure the choke wasnt engaged, loosened the governor arm, turned the governor shaft clockwise as far as it would go, tighten the governor arm to the shaft.
So it would seem to me, that its running rich or perhaps theres another issue??
I checked the deck bearings, blades move freely, belt is routed correctly.
All I know to do at this point, is check the compression psi again.
Clean out the carb one more last time.
With the air filter/cover in place and wide open throttle, I tried to adjust the air screw on the carb, it made no difference whatsoever. Thinking thats a clue and maybe theres junk in the carb or perhaps I missed it before. New fuel filter is in place, lines and tank are clean.
Something makes me think poor compression but I dont wanna jump the gun and have it resleeved or bored, hell, Im not sure what is the standard procedure on these small engines, bored or sleeved?
Any suggestions welcome.
Thanks
Good news:
Governor is in place. Engine fired right up. Everything looks clean and shiny and almost new. No oil shooting out the pvc box. :laughing::thumbsup:
Bad news:
Engine runs at a very very low rpm than youd expect.
If I remove the airfilter/cover (which is brand new), the rpms will increase to what I consider normal but still not quite as powerful as Id expect once the blades are engaged.
The little pvc box or whatever you wanna call it now vents directly to the atmosphere, I disconnected it from the air cleaner.
Sure enough though, if I remove the airfilter/cleaner, the rpms will shoot up, put it back on, they drop down, ya almost think its gonna die but it keeps on running.
Choke operates correctly, as does the throttle blade/linkage.
I adjusted the governor best I know how, by setting the throttle lever to fast, making sure the choke wasnt engaged, loosened the governor arm, turned the governor shaft clockwise as far as it would go, tighten the governor arm to the shaft.
So it would seem to me, that its running rich or perhaps theres another issue??
I checked the deck bearings, blades move freely, belt is routed correctly.
All I know to do at this point, is check the compression psi again.
Clean out the carb one more last time.
With the air filter/cover in place and wide open throttle, I tried to adjust the air screw on the carb, it made no difference whatsoever. Thinking thats a clue and maybe theres junk in the carb or perhaps I missed it before. New fuel filter is in place, lines and tank are clean.
Something makes me think poor compression but I dont wanna jump the gun and have it resleeved or bored, hell, Im not sure what is the standard procedure on these small engines, bored or sleeved?
Any suggestions welcome.
Thanks
#46
J
jhwentworth
Okay, with the air filter off, the engine governor regulates engine RPMs at about 3,000?
Air filter on, the RPMs drop way down?
If both statements are true don't worry about the load on the engine.
The air filter will slightly increase the fuel-air ratio, but not enough to make this difference.
As for as a rebore on the engine; most people replace the engine or junk the mower.
What's the spark plug look like? Sooty and black? What is the compression while starting? Have you checked the key in the magneto? If the spark were seriously retarded you could see the engine not carrying the load (although I don't understand why the air filter would make a difference).
Testing the compression will confirm the valves are working correctly, and a look at the key will verify the timing.
J
jhwentworth
I have good news and bad news.
Engine runs at a very very low rpm than youd expect.
If I remove the airfilter/cover (which is brand new), the rpms will increase to what I consider normal but still not quite as powerful as Id expect once the blades are engaged.
Sure enough though, if I remove the airfilter/cleaner, the rpms will shoot up, put it back on, they drop down, ya almost think its gonna die but it keeps on running.
Choke operates correctly, as does the throttle blade/linkage.
I adjusted the governor best I know how, by setting the throttle lever to fast, making sure the choke wasnt engaged, loosened the governor arm, turned the governor shaft clockwise as far as it would go, tighten the governor arm to the shaft.
So it would seem to me, that its running rich or perhaps theres another issue??
I checked the deck bearings, blades move freely, belt is routed correctly.
All I know to do at this point, is check the compression psi again.
Clean out the carb one more last time.
With the air filter/cover in place and wide open throttle, I tried to adjust the air screw on the carb, it made no difference whatsoever. Thinking thats a clue and maybe theres junk in the carb or perhaps I missed it before. New fuel filter is in place, lines and tank are clean.
Something makes me think poor compression but I dont wanna jump the gun and have it resleeved or bored, hell, Im not sure what is the standard procedure on these small engines, bored or sleeved?
Any suggestions welcome.
Thanks
Okay, with the air filter off, the engine governor regulates engine RPMs at about 3,000?
Air filter on, the RPMs drop way down?
If both statements are true don't worry about the load on the engine.
The air filter will slightly increase the fuel-air ratio, but not enough to make this difference.
As for as a rebore on the engine; most people replace the engine or junk the mower.
What's the spark plug look like? Sooty and black? What is the compression while starting? Have you checked the key in the magneto? If the spark were seriously retarded you could see the engine not carrying the load (although I don't understand why the air filter would make a difference).
Testing the compression will confirm the valves are working correctly, and a look at the key will verify the timing.
#47
I
inline300
I
inline300
Compression cold is between 50 and 55psi
flywheel key is fine, I took the flywheel off and reinstalled during assembly.
put a new spark plug in, ran it a couple minutes, it was definitely darkening.
also noticed fuel spittin out of the carb, intake side as it ran.
she be rich I guess.
I just remembered the timing gear on the crankshaft had came loose, and I just put it back thinking it should be fine, now Im wondering if the timing is off a tooth or not. huh.
flywheel key is fine, I took the flywheel off and reinstalled during assembly.
put a new spark plug in, ran it a couple minutes, it was definitely darkening.
also noticed fuel spittin out of the carb, intake side as it ran.
she be rich I guess.
I just remembered the timing gear on the crankshaft had came loose, and I just put it back thinking it should be fine, now Im wondering if the timing is off a tooth or not. huh.
#48
I
inline300
I
inline300
It was the timing.
Shes running fine now.
Bet the compression psi is a little better too, but I havent checked it, probably wont, it cut the grass fine. I think the dead battery it came with is gonna charge up nice too.
Thanks folks.
Shes running fine now.
Bet the compression psi is a little better too, but I havent checked it, probably wont, it cut the grass fine. I think the dead battery it came with is gonna charge up nice too.
Thanks folks.