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Briggs 17.5 opposed twin will not restart when hot 42A707

#1

troy-built

troy-built

I have a Briggs 17.5 opposed twin that will not restart when hot. I've changed the coil twice it's getting fuel but today I finally figured out it's not firing. It's a 42A707 motor. Now once it cools off after about 30 min it will run like a top until you shut it off. It starts right up when it's cold.
It's sounding like a wire is breaking down if it was a car but i don't know where to look?

Anybody? I don't know what else to look at?

Thanks


#2

M

mechanic mark

Absolutely, when was the last time you removed blower housing, cover over engine, & cleaned cooling fins on each cylinder top & bottom? Do not use water, I use small dental like tools, small wire brushes & a Shop Vac to remove crud from engine. Using water will create electrical & mechanical problems.
Take a look at plugs & gap & inspect spark plug boots.
Post complete model xxxxxx, type xxxx, trim xx, code xxxxxxxx.


#3

troy-built

troy-built

Thanks for the reply.
I took it completely apart last fall to replace the pan gasket. It's clean as a pin as I don't cut grass with it anymore I just use it to pull a trailer. I just have started using it in the last couple of weeks that's when I seen it wouldn't start when hot. It doesn't have to be that hot either. I can let it run for lets say 5 min riding around the yard. You know I just thought of something. I had it sitting in the sun with the hood up yesterday and it had been sitting there for an hour. I tried to start it, nothing so I pushed it in the shade and 20 min later it started right up. So go figure.


#4

troy-built

troy-built

Now I did wash the entire mower last fall before I took it apart. The mower had been sitting in my shed for 10 years before I got it out to work on it. Looking for something to do you know.

The mower ran and started great when I parked it because of the oil leak.


#5

Scrubcadet10

Scrubcadet10

see if you can get it to fire on Parts cleaner or starting fluid when hot.


#6

troy-built

troy-built

Scrubcadet10 said:
see if you can get it to fire on Parts cleaner or starting fluid when hot.
Click to expand...
Yep I tried that and nothing. It's not firing at all until it cools down.


#7

troy-built

troy-built

You know I was thinking about what was said about washing a mower.
I blow my mowers of every time I cut grass. And I wash them every 3rd time I use them and I have NEVER had a problem with them starting or anything like that.
I guess it could be from sitting so many years?


#8

Scrubcadet10

Scrubcadet10

Have you checked for spark when it's hot with an inline tester?
Being a flat head engine, it could be the valve clearances (Between the lifter and valve) have gotten too tight and only manifest the issue when hot (metal expands, decreasing the gap even more)


#9

troy-built

troy-built

Scrubcadet10 said:
I'm not seeing the model numbers and engine numbers in my crystal ball either
(must need a new crystal ball)
Click to expand...

LOL I like that. I always say we need to contact Carnack. LOL


#10

troy-built

troy-built

Scrubcadet10 said:
Have you checked for spark when it's hot with an inline tester?
Being a flat head engine, it could be the valve clearances (Between the lifter and valve) have gotten too tight and only manifest the issue when hot (metal expands, decreasing the gap even more)
Click to expand...
Now that's one thing I haven't tried but I will for sure. Thank you.

Would you know what the valve gap is on my mower? Numbers above. LOL


#11

Scrubcadet10

Scrubcadet10

troy-built said:
LOL I like that. I always say we need to contact Carnack. LOL
Click to expand...
1630887565323.png
LOL yep,
That's my signature that appears with every post, from a former member


#12

H

hlw49

Scrubcadet10 said:
see if you can get it to fire on Parts cleaner or starting fluid when hot.
Click to expand...
Don't use starting fluid use gum out carb cleaner it won't blow the head off your engine.


#13

Scrubcadet10

Scrubcadet10

Yeah.


#14

troy-built

troy-built

hlw49 said:
Don't use starting fluid use gum out carb cleaner it won't blow the head off your engine.
Click to expand...
I use very little when I do use it. A little goes a long way. But either one doesn't work. I think the next thing I'm going to do is adjust the valves. When I find out what they are set at.


#15

Scrubcadet10

Scrubcadet10

Keep in mind adjusting valves is a little more involved on a flat head than an OHV.
you need a bench grinder or something similar to take a slight amount of material off the valve stem end to reopen the clearance.... of course, that is if the valves are out of adjustment.

Google Drive: Sign-in

Access Google Drive with a Google account (for personal use) or Google Workspace account (for business use).
drive.google.com

Valve Clearance (Cold)
Springs Installed
Intake .004” – .006” (0.10 – 0.15 mm)
Exhaust .007” – .009” (0.17 – 0.22 mm)


#16

troy-built

troy-built

Scrubcadet10 said:
Keep in mind adjusting valves is a little more involved on a flat head than an OHV.
you need a bench grinder or something similar to take a slight amount of material off the valve stem end to reopen the clearance.... of course, that is if the valves are out of adjustment.

Google Drive: Sign-in

Access Google Drive with a Google account (for personal use) or Google Workspace account (for business use).
drive.google.com

Valve Clearance (Cold)
Springs Installed
Intake .004” – .006” (0.10 – 0.15 mm)
Exhaust .007” – .009” (0.17 – 0.22 mm)
Click to expand...
Thank you, I was wondering about that and thanks for the manual link I haven't had any luck finding one.


#17

H

hlw49

troy-built said:
I use very little when I do use it. A little goes a long way. But either one doesn't work. I think the next thing I'm going to do is adjust the valves. When I find out what they are set at.
Click to expand...
Gum out carb cleaner will no blow up your engine you can start it up and spray it in the carb and have someone else drive it in the shop while you keep it running on the stuff. Do it all the time.


#18

troy-built

troy-built

hlw49 said:
Gum out carb cleaner will no blow up your engine you can start it up and spray it in the carb and have someone else drive it in the shop while you keep it running on the stuff. Do it all the time.
Click to expand...
Cool, I understand.
But if I have to keep something running with carb cleaner or what ever for long, I just stop and find out why it's not running right. I work on all of my own stuff myself I don't take anything to a shop.
I restored Corvettes for 35 years so working on things isn't a problem for me. But with trouble shooting it's good to ask others just in case they have had the same problem. Hence my question above.

But thanks anyways for the info.


#19

troy-built

troy-built

You know I have read a LOT of threads on here about motors not restarting when hot not just briggs, and I have read very few threads that figured out what the problem was. Why is that? Do people just give up? I don't understand.
I haven't worked on my mower for a few days as I like to get away from something like this to think it over. I will get back on it in a day or so. I have also thought and you know when I turn the mower off it will start right up just as long as you do it before 3 min pass. That's very odd it's got to be heat related.
I will figure this out because it looks like very few people on here have. At least that's what I have read.

Stay safe all.


#20

B

bertsmobile1

We know why engine will not restart when hot
the problem is almost no one comes back with a
" the problem ended up being xyz, thank you"
so when others like you search, you see lots of suggestions but no solutions.

Without the engine right in front of us, all we can do is give you some tests to do .
You come back with the results of the tests then we can make a diagnosis

Only 3 reasons why a hot engine does not restart
1) bad spark
2) wrong fuel : air ratio
3) sticky valves

Having read through all of the posts and in particular the last one I would be looking at overheating .
So after 3 minutes with no airflow the carb has gotten so hot the fuel is vapourising in the float bowl or fuel lines
A lot of engines require a heat shield to prevent the fuel boiling in the fuel lines


#21

troy-built

troy-built

bertsmobile1 said:
We know why engine will not restart when hot
the problem is almost no one comes back with a
" the problem ended up being xyz, thank you"
so when others like you search, you see lots of suggestions but no solutions.

Without the engine right in front of us, all we can do is give you some tests to do .
You come back with the results of the tests then we can make a diagnosis

Only 3 reasons why a hot engine does not restart
1) bad spark
2) wrong fuel : air ratio
3) sticky valves

Having read through all of the posts and in particular the last one I would be looking at overheating .
So after 3 minutes with no airflow the carb has gotten so hot the fuel is vapourising in the float bowl or fuel lines
A lot of engines require a heat shield to prevent the fuel boiling in the fuel lines
Click to expand...
Hi, Thank you that's what I was looking for a little input. It always helps when there is more than one person is thinking.
{Without the engine right in front of us, all we can do is give you some tests to do .} That's all I was asking for. And I do understand about not having it in front of you I'm on a couple other forums and it's tough sometimes. But I always try to give Ideas what to look for.

Many thanks that has been very helpful.


#22

S

slomo

mechanic mark said:
Absolutely, when was the last time you removed blower housing, cover over engine, & cleaned cooling fins on each cylinder top & bottom? Do not use water, I use small dental like tools, small wire brushes & a Shop Vac to remove crud from engine. Using water will create electrical & mechanical problems.
Click to expand...
Please repeat saying this for those in the back.


#23

T

troynstan

If you lose spark when the engine is hot, it may be the coil overheating. It happens alot on push mowers. Although, if this is a twin cylinder, you would think it would at least run on 1 cyl. I would check for spark on both cylinders when cold, then again when hot and see if it is spark related. If you sprayed starting fluid in the carb when hot and it didn't fire, then it is either flooding, losing spark, or losing compression.


#24

W

woodysand

I think that motor has a wire coming from the coil that when you turn the key off it grounds that wire which kills the engine. Try tracing that from the coil and disconnecting it from the switch. If it will then start up when it’s hot you have something wrong either in the wire or the switch.


#25

A

Ariens A19A42

Could be valve adjustment . Mine has a hard time cranking if it stopped on the compression stroke and think it's the vavles making it hard to turn over. But it will always run if I by had spin it past the compression stroke. Hope its not the compression release. Doesn't have a whole lot of hours on the Briggs 19 hp motor. It would backfire bad when I would shut it down until I figured out how to shut it down so it didn't Hope when it did backfire it didn't break the Compression Release.


#26

Scrubcadet10

Scrubcadet10

troynstan said:
If you lose spark when the engine is hot, it may be the coil overheating. It happens alot on push mowers. Although, if this is a twin cylinder, you would think it would at least run on 1 cyl. I would check for spark on both cylinders when cold, then again when hot and see if it is spark related. If you sprayed starting fluid in the carb when hot and it didn't fire, then it is either flooding, losing spark, or losing compression.
Click to expand...
These opposed twins use 1 coil for 2 cylinders.


#27

Scrubcadet10

Scrubcadet10

Ariens A19A42 said:
Could be valve adjustment . Mine has a hard time cranking if it stopped on the compression stroke and think it's the vavles making it hard to turn over. But it will always run if I by had spin it past the compression stroke. Hope its not the compression release. Doesn't have a whole lot of hours on the Briggs 19 hp motor. It would backfire bad when I would shut it down until I figured out how to shut it down so it didn't Hope when it did backfire it didn't break the Compression Release.
Click to expand...
Opposed twins don't have a compression relief mechanism on the camshaft.


#28

peteco

peteco

Coil problem, when hot, low spark. Try change the coil. Common problem in VW air cooled engines.


#29

troy-built

troy-built

slomo said:
Please repeat saying this for those in the back.
Click to expand...
Are you saying to wash a mower or to not wash a mower? That wasn't clear. I did answer his question by the way.

I myself will continue washing my mowers and everything else I own. It's NO different than washing a motorcycle to me. I have a 2013 zero turn that looks as good today as it did the day I bought it.

Water isn't the problem with my mower I'm sure it's just age.
Thanks


#30

beg

beg

my guess is your coil is bad had the same problem on two of my Toro ccr1000 snowblowers wound not start after being warmed up


#31

troy-built

troy-built

I want to thank everyone for chiming in that has given me some ideas. That's what I was hoping for. I'm going to go work on it for a while and check the compression when it's hot and won't restart. I'll be back later to tell you what I find out.

Many thanks again to all.


#32

Scrubcadet10

Scrubcadet10

troy-built said:
I have a Briggs 17.5 opposed twin that will not restart when hot. I've changed the coil twice it's getting fuel but today I finally figured out it's not firing. It's a 42A707 motor. Now once it cools off after about 30 min it will run like a top until you shut it off. It starts right up when it's cold.
It's sounding like a wire is breaking down if it was a car but i don't know where to look?

Anybody? I don't know what else to look at?

Thanks
Click to expand...
People, go back and read.


#33

troy-built

troy-built

beg said:
my guess is your coil is bad had the same problem on two of my Toro ccr1000 snowblowers wound not start after being warmed up
Click to expand...
I tried a new coil and it did the EXACT same thing. Is it common to get a bad new coil?


#34

troy-built

troy-built

Scrubcadet10 said:
People, go back and read.
Click to expand...
LOL I was going to do that but you beat me to it. LOL Thanks


#35

L

lbrac

If the engine is not firing, valve clearances shouldn't be of concern until it is firing. You can check the compression with a gauge while cold, then when hot, to see if a valve gets lifted when hot. Coils are prone to heat related failure, causing problems that can resolve when they cool. As they expand and contract with the temperature, damaged insulation can cause them to short out, or an internal broken wire can open the circuit, etc. Engine heat transfers from higher to lower temperature areas when the engine is stopped because the air flow stops.

I've had trouble with a flooding carburetor when the engine was stopped. The carb is between and above the cylinders and heats up when the engine is stopped, this caused the gasoline to boil over into the intake manifold. Check the plugs to see if they are wet when it doesn't start when hot. After it sits a few minutes when hot, look for fuel puddling in the intake manifold using a light, by looking through the carburetor w/ the choke and throttle wide open. I lowered the float level slightly to resolve that problem. But again, not a lack of spark issue. Systematic troubleshooting helps pinpoint causes for problems.


#36

S

slomo

troy-built said:
Are you saying to wash a mower or to not wash a mower? That wasn't clear. I did answer his question by the way.

I myself will continue washing my mowers and everything else I own. It's NO different than washing a motorcycle to me. I have a 2013 zero turn that looks as good today as it did the day I bought it.

Water isn't the problem with my mower I'm sure it's just age.
Thanks
Click to expand...
Recommended to NOT wash a mower. Rust, corroded wires and connectors and so on. Power washers could get water in the oil sump with all that pressure. Key not working, corroded grounds to name some more.

Use compressed air, ScrubCadet 10 brushes, baby bottle brushes, degreaser then blow off and so on.

Use what ever method you have to clean the engine YEARLY or more if you scalp or bag. Some baggers dump a lot of grass on top of the engine.


#37

S

slomo

Has the coil been checked? Might want to look at that. :p


#38

K

KuBoTah

troy-built said:
I have a Briggs 17.5 opposed twin that will not restart when hot. I've changed the coil twice it's getting fuel but today I finally figured out it's not firing. It's a 42A707 motor. Now once it cools off after about 30 min it will run like a top until you shut it off. It starts right up when it's cold.
It's sounding like a wire is breaking down if it was a car but i don't know where to look?

Anybody? I don't know what else to look at?

Thanks
Click to expand...
I am thinking about "what is the obvious"?
On my old B&S motors I create a ground to stop the sparkplug from firing. There is a kill switch for same with a small wire going to a ground.
Today's mowers have the "deadman switch" (maybe the wrong name) which requires one to hold the lever against the Push Bar. When released; the mower stops. First place I'd look is the complete deadman system, handles, springs wires to ground out the ignition. It could be that the ground wire switch is too close to the actual ground, thus the mower won't start when everything is hot. I'd also look for bent pieces around the springs, small wires and cables. Also look to see if the ground wire has too much insulation cut back on it (or the wire is loose), and the hot motor makes the switch get too close to a ground.


#39

mitchstein443

mitchstein443

More then likely the gap on the points is off, too close.. when it heats up the points expand closing the gap too close to make the spark(seperate enough for the coil to build up voltage)..

I had the opposite problem with my briggs opposed twin, the points wore down so much that the gap was too large for a strong spark, so if it was 90 degrees outside and it was sitting in the su it fired up ran weak for a few minutes then ran strong as could be once warmed up. I had to dig deep into my car knowledge (back to the 1960's) to figure it out.. Of course I did everything you did, cleaned everything, replaced plugs coils, wires, tried starting fluid etc etc.. and it turned out to be the stupid points..


#40

Scrubcadet10

Scrubcadet10

troy-built said:
I tried a new coil and it did the EXACT same thing. Is it common to get a bad new coil?
Click to expand...
Depends if it's an OEM Briggs part or aftermarket? I've used a few aftermarket coils
slomo said:
Recommended to NOT wash a mower. Rust, corroded wires and connectors and so on. Power washers could get water in the oil sump with all that pressure. Key not working, corroded grounds to name some more.

Use compressed air, ScrubCadet 10 brushes, baby bottle brushes, degreaser then blow off and so on.

Use what ever method you have to clean the engine YEARLY or more if you scalp or bag. Some baggers dump a lot of grass on top of the engine.
Click to expand...
????


#41

mitchstein443

mitchstein443

KuBoTah said:
I am thinking about "what is the obvious"?
On my old B&S motors I create a ground to stop the sparkplug from firing. There is a kill switch for same with a small wire going to a ground.
Today's mowers have the "deadman switch" (maybe the wrong name) which requires one to hold the lever against the Push Bar. When released; the mower stops. First place I'd look is the complete deadman system, handles, springs wires to ground out the ignition. It could be that the ground wire switch is too close to the actual ground, thus the mower won't start when everything is hot. I'd also look for bent pieces around the springs, small wires and cables. Also look to see if the ground wire has too much insulation cut back on it (or the wire is loose), and the hot motor makes the switch get too close to a ground.
Click to expand...
good point! but an easy way to know is to remove the negative wire from the coil and see if it fires then.. if it does then it is the kill wire (ground), if it doesn't then it is something else..


#42

mitchstein443

mitchstein443

slomo said:
Recommended to NOT wash a mower. Rust, corroded wires and connectors and so on. Power washers could get water in the oil sump with all that pressure. Key not working, corroded grounds to name some more.

Use compressed air, ScrubCadet 10 brushes, baby bottle brushes, degreaser then blow off and so on.

Use what ever method you have to clean the engine YEARLY or more if you scalp or bag. Some baggers dump a lot of grass on top of the engine.
Click to expand...
oh, thats a load of malarky, been powerwashing small engines for over 35 years, its the first thing I always did before servicing and on my own equipment at least once a month, NEVER EVER had water get in the air cleaner/carb or oil. and I have washed every small motor from the predators to the 1960's opoosed twins..

I also do the samething on my camaro, yukon, xterra and prius.. never once had any issues with corroded wires or water damage..

However, if you do not kow what an air cleaner is, or what an oil cap is, hen don't power wash it, matter of fact do not touch it at all, go get a book and learn how an engine works before touching it at all..


#43

troy-built

troy-built

Scrubcadet10 said:
Depends if it's an OEM Briggs part or aftermarket? I've used a few aftermarket coils

????
Click to expand...
It was an aftermarket coil.


#44

S

slomo

mitchstein443 said:
oh, thats a load of malarky, been powerwashing small engines for over 35 years, its the first thing I always did before servicing and on my own equipment at least once a month, NEVER EVER had water get in the air cleaner/carb or oil. and I have washed every small motor from the predators to the 1960's opoosed twins..

I also do the samething on my camaro, yukon, xterra and prius.. never once had any issues with corroded wires or water damage..

However, if you do not kow what an air cleaner is, or what an oil cap is, hen don't power wash it, matter of fact do not touch it at all, go get a book and learn how an engine works before touching it at all..
Click to expand...
Would be fabulous to live in a rust and corrosion free neighborhood like you. Guess I need to move.


#45

S

slomo

Scrubcadet10 said:
Depends if it's an OEM Briggs part or aftermarket? I've used a few aftermarket coils

????
Click to expand...
What was so funny? I too like a good joke. What did I miss Scrubcadet10?


#46

troy-built

troy-built

Ok I went out and worked on it for a while.
This is about as scientific as I get.
It's not as hot here today so I'm sure that's why the times are off from before. I checked the comp cold, the right cyl was 110 lbs and the left was also 110lbs.
I went and got my car timing light before I started it. Yea I know who has those these days. I checked the fire and both sides they were strong. I cranked it, it started right up. I went for a ride for 10 min. Turned it off at 23 after, started it at 25, 27, 30 and 40 after. It started every time.
Went for another ride for about 5 min. Cut it off. Tried starting it a 55 after NOTHING. Hooked up my timing light and just a little bit of spark once and a while on either cyl unhooked the ground on the coil the same thing no crank.
Then I did a compression check hot the right cyl was 110. and the Lt was 107. Not to bad I don't think.

What do you guys think the coil? The new one was bad? I have the old one back on there now.


#47

R

Ranamow

beg said:
my guess is your coil is bad had the same problem on two of my Toro ccr1000 snowblowers wound not start after being warmed up
Click to expand...
That was my thought as well. I had 6.5 Briggs with the same issue, would start and run great but if you shut off, nothing. Then you had to wait a half hour and you were good to go! I finally put an old coil on that I had laying around, and works perfect.


#48

Scrubcadet10

Scrubcadet10

slomo said:
What was so funny? I too like a good joke. What did I miss Scrubcadet10?
Click to expand...
You missed part of my quote.
1631131544943.png


#49

Scrubcadet10

Scrubcadet10

troy-built said:
Ok I went out and worked on it for a while.
This is about as scientific as I get.
It's not as hot here today so I'm sure that's why the times are off from before. I checked the comp cold, the right cyl was 110 lbs and the left was also 110lbs.
I went and got my car timing light before I started it. Yea I know who has those these days. I checked the fire and both sides they were strong. I cranked it, it started right up. I went for a ride for 10 min. Turned it off at 23 after, started it at 25, 27, 30 and 40 after. It started every time.
Went for another ride for about 5 min. Cut it off. Tried starting it a 55 after NOTHING. Hooked up my timing light and just a little bit of spark once and a while on either cyl unhooked the ground on the coil the same thing no crank.
Then I did a compression check hot the right cyl was 110. and the Lt was 107. Not to bad I don't think.

What do you guys think the coil? The new one was bad? I have the old one back on there now.
Click to expand...
Sure seems to be coil related...
could you post a link to the one you bought?


#50

troy-built

troy-built

Scrubcadet10 said:
Sure seems to be coil related...
could you post a link to the one you bought?
Click to expand...
Sorry I don't have a link, I bought it on amazon just because it was easy. It wasn't a B&S, I'm going tomorrow to our local mower parts house and buy a real one.


#51

Scrubcadet10

Scrubcadet10

Before you do that.... you wouldn't mind posting the Type number of the engine? it's the numbers after the Model...
some of these engines used The coil, and points and condenser.


#52

troy-built

troy-built

Scrubcadet10 said:
Before you do that.... you wouldn't mind posting the Type number of the engine? it's the numbers after the Model...
some of these engines used The coil, and points and condenser.
Click to expand...
I don't mind I'll go out and look.


#53

troy-built

troy-built

I'll do one better than that what about a pic of the trim tag?

Attachments





#54

troy-built

troy-built

Here's a pic of the motor just because I was there. LOL Like I said before it's clean.

Attachments





#55

Scrubcadet10

Scrubcadet10

Thank ya.... just uses the magnetron coil, and no points etc.
That number is the exact same as my opposed twin that i have too...


#56

troy-built

troy-built

Scrubcadet10 said:
Thank ya.... just uses the magnetron coil, and no points etc.
That number is the exact same as my opposed twin that i have too...
Click to expand...
Awesome, Thank you you gave been a great deal of help,


#57

B

bertsmobile1

troynstan said:
If you lose spark when the engine is hot, it may be the coil overheating. It happens alot on push mowers. Although, if this is a twin cylinder, you would think it would at least run on 1 cyl. I would check for spark on both cylinders when cold, then again when hot and see if it is spark related. If you sprayed starting fluid in the carb when hot and it didn't fire, then it is either flooding, losing spark, or losing compression.
Click to expand...
the horizontally opposed layout uses a single double ended coil so one plug the spark goes from the inner to outer electrodes and the other sparks from the outer to the inner
These types of coils work really well on high reving things like transverse 4 motorcycles with battery coil ignitions but not so good on slow reving things like lawnmowers with magnetos
But of course they won't fire on either cylinder if the coil is bad, in fact the quickest diagnosis is to slip an in line spark tester on each cylinder then stand in front of the engine and watch for both testers flashing at the same time .
And you diagnose a weak coil if you get no spark at either end and then get a spark when you ground one plug lead.


#58

troy-built

troy-built

Scrubcadet10 said:
Thank ya.... just uses the magnetron coil, and no points etc.
That number is the exact same as my opposed twin that i have too...
Click to expand...
Hi, Would you have the correct part number of the coil I should be looking for? Thanks


#59

troy-built

troy-built

bertsmobile1 said:
the horizontally opposed layout uses a single double ended coil so one plug the spark goes from the inner to outer electrodes and the other sparks from the outer to the inner
These types of coils work really well on high reving things like transverse 4 motorcycles with battery coil ignitions but not so good on slow reving things like lawnmowers with magnetos
But of course they won't fire on either cylinder if the coil is bad, in fact the quickest diagnosis is to slip an in line spark tester on each cylinder then stand in front of the engine and watch for both testers flashing at the same time .
And you diagnose a weak coil if you get no spark at either end and then get a spark when you ground one plug lead.
Click to expand...
That's interesting. I don't have a way to check both sides at once. But when I checked each one one at a time they both only fired every once and a while.


#60

B

bertsmobile1

troy-built said:
That's interesting. I don't have a way to check both sides at once. But when I checked each one one at a time they both only fired every once and a while.
Click to expand...
Should fire every stroke
Get a white paint pen and mark the flywheel at TDC
Every time the white mark goes past the plug should fire
If not then the coil is toast
These coils are very sensitive to both the spark plug and the plug gap .
What plugs are you using ?
Very common for the monkey behind the parts counter to grab the wrong bannana when you say Briggs plug .


#61

Scrubcadet10

Scrubcadet10

troy-built said:
Hi, Would you have the correct part number of the coil I should be looking for? Thanks
Click to expand...
1631144889995.png


#62

troy-built

troy-built

bertsmobile1 said:
These coils are very sensitive to both the spark plug and the plug gap .
What plugs are you using ?
Click to expand...
I don't have the number in front of me but I know it's a champion plug. I will look tomorrow. I will say one thing I regaped the plugs today after reading over the manual, they were to wide and it seemed to run better.


#63

troy-built

troy-built

Scrubcadet10 said:
View attachment 58259
Click to expand...
Thank you, I have found a couple of the older 394891 style like what is on my mower now. Man the newer part number looks totally different. Should I go with the older style? Or will it matter?


#64

Scrubcadet10

Scrubcadet10

Probably won't matter, if you get/order the 394891, most likely you will receive the 590781.


#65

troy-built

troy-built

Scrubcadet10 said:
Probably won't matter, if you get/order the 394891, most likely you will receive the 590781.
Click to expand...
I have found a few NOS 394891 in the original B&S boxes. The new style 590781s are a good bit cheaper and seem to be all made in china. That's where the bad one I have now that I bought was made. Most of the time you get what you pay for I guess.

Thanks again for your help.


#66

matt man

matt man

I have same. This is the second ignition coil that I have put on it.


#67

troy-built

troy-built

matt man said:
I have same. This is the second ignition coil that I have put on it.
Click to expand...
I hope this next one last as long as the first one did. LOL


#68

D

Deerefan

Scrubcadet10 said:
Depends if it's an OEM Briggs part or aftermarket? I've used a few aftermarket coils

????
Click to expand...


#69

troy-built

troy-built

^^^^^^^ LOL Your first post in 7 years and nothing was said? Why bother? ^^^^^^^


#70

Scrubcadet10

Scrubcadet10

troy-built said:
^^^^^^^ LOL Your first post in 7 years and nothing was said? Why bother? ^^^^^^^
Click to expand...
:LOL:


#71

troy-built

troy-built

LOL ^^^^^^ Yep LOL


#72

troy-built

troy-built

It's showing my coil will be here today. I will let you know what happens.


#73

S

slomo

troy-built said:
You know I have read a LOT of threads on here about motors not restarting when hot not just briggs, and I have read very few threads that figured out what the problem was. Why is that? Do people just give up? I don't understand.
Click to expand...
Most people lack the common courtesy to come back and say Thank You!

Most want everything handed to them on a chrome platter. And have a $1300 cell phone, these peoples......


#74

S

slomo

Just put one of these on top of the coil filled with ice. You can mow all day long. Easy right?

1631384923023.png


#75

troy-built

troy-built

slomo said:
Most people lack the common courtesy to come back and say Thank You!

Most want everything handed to them on a chrome platter. And have a $1300 cell phone, these peoples......
Click to expand...
I Know what you mean. I'm on a few other forums and that's the way it is there also. Believe me I will be here until the end. Hopefully someone will read my problems and will help them fix there mower.

LOL That's why I still have a flip phone I guess. LOL


#76

troy-built

troy-built

slomo said:
Just put one of these on top of the coil filled with ice. You can mow all day long. Easy right?

View attachment 58295
Click to expand...
Yep that would work or just pour ice tea on it when your taking a break. LOL


#77

troy-built

troy-built

Well I got the new coil installed today. Lets see how it works out once it gets hot. I was lucky to find an original coil MVC-001S.JPGMVC-004S.JPG

Attachments







#78

troy-built

troy-built

I will say it runs better than it ever has with the new coil.


#79

Scrubcadet10

Scrubcadet10

ALRIIIIIGHT!!!! (y) (y) (y) (y)


#80

S

slomo

Yipee!! She's a runner.

Okay, that filthy engine is next. Remove the engine shroud again and clean all that oily dirt mud pack muck off the top of the engine block and cooling fins. This is a YEARLY procedure in your engine manual. All that dirt and oil will insulate the block and fins retarding air cooling. Neglect this and you are looking at future engine damage. Look behind mufflers and so on all around the block. Some engines might have a block hugging cover to keep cooling air close to the block. Remove and clean behind those if you have one. Again look all around and on the bottom of the block too. Clean it like a new engine. Compressed air, Scrubcadet10 brushes and so on.

1631505448679.png

Also probably a good idea on that rich runner to pull the heads and de-carbonize the cylinders, valves and heads. This is also in your engine manual.


#81

troy-built

troy-built

slomo said:
Yipee!! She's a runner.

Okay, that filthy engine is next. Remove the engine shroud again and clean all that oily dirt mud pack muck off the top of the engine block and cooling fins.
Click to expand...
LOL There is none. Remember I said I pulled the motor to replace the pan gasket. It's clean as a whistle.

Man was I wrong, You have a good eye. I totally missed that dirt until you mentioned it and then I seen it in the pic. That's why I like taking pics when I'm working on something because I couldn't see down in there because it was dark and I took the pic with the flash on. The dirt was only in that one spot and I'd be willing to bet that little bit of stopped up fins was making that head get hot under the coil.

This is exactly why I like people chiming in on a forum.

Many thanks


#82

troy-built

troy-built

Oh by the way why is it so hard to get to this web site. It takes me no less than 5 tries everytime sometimes more to get on here. I don't have a problem anywhere else.


#83

Scrubcadet10

Scrubcadet10

troy-built said:
Oh by the way why is it so hard to get to this web site. It takes me no less than 5 tries everytime sometimes more to get on here. I don't have a problem anywhere else.
Click to expand...
what issues are you having? takes a long time to load?
none on my end.


#84

troy-built

troy-built

Scrubcadet10 said:
what issues are you having? takes a long time to load?
none on my end.
Click to expand...
I have the forum link saved on my PC and when I click on it it just sits and spins. I can click on something else and it pops right up. I've even typed in the name and it will do the same on duck duck go or google. I close the link that hasn't opened start all over with a new link and it might not open and it might.

I have no idea what the problem is this is the ONLY place I have trouble getting on to.


#85

troy-built

troy-built

Ok here you go guys hope this thread helps people in the future. I haven't run it much yet but I'd be willing to bet my starting problem is fixed. I will let you know if it isn't. MVC-015S.JPG

Attachments







#86

troy-built

troy-built

Ok I have another question, On these nikki 4 screw carbs what's involved in richning them up the mower is running lean as it's surging. I can pull the choke out just a little and it smooths out. Or should I find an older 3 screw carb? Thanks


#87

Scrubcadet10

Scrubcadet10

Probably needs a good carburetor cleaning. I don't think the 4 screw have any fuel adjustments, some do and some don't.


#88

troy-built

troy-built

Scrubcadet10 said:
Probably needs a good carburetor cleaning. I don't think the 4 screw have any fuel adjustments, some do and some don't.
Click to expand...
Yea that's what I've seen that the 4 screw carbs don't have any adjustment. Well they do but it's behind the welch plug. The 3 screw can be adjusted.

This has been a learning curve and I'm learning a lot. Small engines is something I have never worked on but I will say I'm really enjoying it

Thanks everyone that has chimed in to help.


#89

troy-built

troy-built

Scrubcadet10 said:
what issues are you having? takes a long time to load?
none on my end.
Click to expand...
I'm beginning to believe it's all the pop up adds that's slowing things down for me. Oh well.


#90

B

bertsmobile1

troy-built said:
I'm beginning to believe it's all the pop up adds that's slowing things down for me. Oh well.
Click to expand...
Yep.
When the adds were static they loaded quickly
Now they are dynamic so they take a long time to load and the tiny routines to make the adds move & chage theem hy-jacks the processor continually.
every time the add changes on the page the server interrogates ( snoops ) your cashe & history in order to place the add you are most likely to read.'All of this take time & uses up download allocations .
Good logic behind it and probably works well on a brand new state of art computer with 10Gb+ of rams , SSD hard drives and multiple multi core processors runningat astronomical speeds that the computer wankers play with .
Some of the scripts that were really bogging my computer down were trying to access Microsoft Tool Box routines , which not being a Windoze box it could no find so it went into an endless loop till I eventually terminated the script at which time the browser generally crashed .


#91

troy-built

troy-built

bertsmobile1 said:
Yep.
When the adds were static they loaded quickly
Now they are dynamic so they take a long time to load and the tiny routines to make the adds move & chage theem hy-jacks the processor continually.
every time the add changes on the page the server interrogates ( snoops ) your cashe & history in order to place the add you are most likely to read.'All of this take time & uses up download allocations .
Good logic behind it and probably works well on a brand new state of art computer with 10Gb+ of rams , SSD hard drives and multiple multi core processors runningat astronomical speeds that the computer wankers play with .
Some of the scripts that were really bogging my computer down were trying to access Microsoft Tool Box routines , which not being a Windoze box it could no find so it went into an endless loop till I eventually terminated the script at which time the browser generally crashed .
Click to expand...
Well there you go just as I thought. Thanks for confirming my suspicions.


#92

troy-built

troy-built

troy-built said:
Well there you go just as I thought. Thanks for confirming my suspicions.
Click to expand...
It's sure a pain in the ass. I couldn't even edit this post. Oh well thanks all.


#93

S

slomo

troy-built said:
Oh by the way why is it so hard to get to this web site. It takes me no less than 5 tries everytime sometimes more to get on here. I don't have a problem anywhere else.
Click to expand...
No issues at home or work. Check your gateway for congestion or reboot. Run an ad blocker for sure. I prefer Firefox as I despise goo'gal.


#94

S

slomo

troy-built said:
LOL There is none. Remember I said I pulled the motor to replace the pan gasket. It's clean as a whistle.

Man was I wrong, You have a good eye. I totally missed that dirt until you mentioned it and then I seen it in the pic. That's why I like taking pics when I'm working on something because I couldn't see down in there because it was dark and I took the pic with the flash on. The dirt was only in that one spot and I'd be willing to bet that little bit of stopped up fins was making that head get hot under the coil.

This is exactly why I like people chiming in on a forum.

Many thanks
Click to expand...
Another set of eyes is worth a bunch at times. We are all getting older and crap, where are my reading glasses again??? LOL


#95

troy-built

troy-built

slomo said:
No issues at home or work. Check your gateway for congestion or reboot. Run an ad blocker for sure. I prefer Firefox as I despise goo'gal.
Click to expand...
Yea I also use firefox... And glasses too... LOL


#96

Scrubcadet10

Scrubcadet10

troy-built said:
Yea I also use firefox... And glasses too... LOL
Click to expand...
Try using the DuckDuckGo search engine
duckduckgo.com

DuckDuckGo - Your protection, our priority.

The Internet privacy company that empowers you to seamlessly take control of your personal information online, without any tradeoffs.
duckduckgo.com duckduckgo.com


#97

troy-built

troy-built

Scrubcadet10 said:
Try using the DuckDuckGo search engine
duckduckgo.com

DuckDuckGo - Your protection, our priority.

The Internet privacy company that empowers you to seamlessly take control of your personal information online, without any tradeoffs.
duckduckgo.com duckduckgo.com
Click to expand...
That's my first choice then I try others. For some reason it's not as hard today to get on here as it was several days ago.
I'm using duck go right now.


#98

S

slomo

It's not a search engine like goo'gal or duck and cover. More like everyone without ad blockers getting bombarded with ads waiting on all the ads to load from all those different servers on the interscreen.


#99

troy-built

troy-built

slomo said:
It's not a search engine like goo'gal or duck and cover. More like everyone without ad blockers getting bombarded with ads waiting on all the ads to load from all those different servers on the interscreen.
Click to expand...
You know it's funny since I said something about this site being slow it's no problem getting on here anymore. LOL I should have said something sooner. LOL


#100

troy-built

troy-built

I have a question. Where would be a good place to go to ask about a Toro horse tiller? I have a 8 hp and I don't have a manual. Many thanks


#101

Scrubcadet10

Scrubcadet10

troy-built said:
I have a question. Where would be a good place to go to ask about a Toro horse tiller? I have a 8 hp and I don't have a manual. Many thanks
Click to expand...
Toro.com or your local Toro dealer


#102

troy-built

troy-built

Scrubcadet10 said:
Toro.com or your local Toro dealer
Click to expand...
Thank you,

Man you wouldn't believe how much faster this forum loads now. I should have said something sooner.


#103

troy-built

troy-built

Ok update time. It finally stopped raining enough here for me to get the Murry out and test it out. After about a 10 min ride I stopped for a bit. Went to start it and the same thing no start. After about 20 min it started right up. Oh well!!!

Ok I'm back to square one but I'm not giving up as it's running better than it ever has. Hell it might be fixing to blow up.. LOL


#104

troy-built

troy-built

LOL I don't blame you guys I don't know what to say either. LOL


#105

Scrubcadet10

Scrubcadet10



#106

troy-built

troy-built

Scrubcadet10 said:
Click to expand...
I would love to have time to watch such a thing but I just don't have the time. Someone with less to do might enjoy it. Now back to more important things.
Oh by the way this place has gotten very slow again, Oh well.


#107

B

bertsmobile1

troy-built said:
Ok update time. It finally stopped raining enough here for me to get the Murry out and test it out. After about a 10 min ride I stopped for a bit. Went to start it and the same thing no start. After about 20 min it started right up. Oh well!!!

Ok I'm back to square one but I'm not giving up as it's running better than it ever has. Hell it might be fixing to blow up.. LOL
Click to expand...
Get yourself a can of freeze spray
Most electronics stores keep it for testing circuit boards with.
When the engine is hot, spray the magneto magnet in the flywheel with the freeze spray till it is at room temprature.
Magnets loose magnetism as they get hotter
As this is a quite old engine it just might be that the magnets have weakened to the "marginal state" where at the slow cranking speeds they just can not produce a spark when hot


#108

troy-built

troy-built

bertsmobile1 said:
Get yourself a can of freeze spray
Most electronics stores keep it for testing circuit boards with.
When the engine is hot, spray the magneto magnet in the flywheel with the freeze spray till it is at room temprature.
Magnets loose magnetism as they get hotter
As this is a quite old engine it just might be that the magnets have weakened to the "marginal state" where at the slow cranking speeds they just can not produce a spark when hot
Click to expand...
Now that's a thought I haven't thought of and that makes a lot of sense. Thank you so much for your help.


#109

B

bertsmobile1

You get used to these sorts of things when you play with 100 year old motorcycles.
It is fairly common for them to clutch start but not kick start as the magnets get weak.
So I can kick start the bike first thing in the morning or after it has sat for about 2 hours, but stop the engine for refuling and you better have a reasonable hill near by ,
Not some thing I wouldhave thought about with a mower, but the same applies spin at 1000 rpm and get a spark, spin at 400 rpm cranking speed and no stark.
However from time to time I do see a hand held that will throw a nice spark with no plug installed but won't throw a spark when the plug is in & you are pulling agains compression


#110

troy-built

troy-built

Ok Well since I'm back here with another problem I will give an update on this thread. I believe I fixed my no start problem, I think. I took off all the heat shielding and it seems to be fixed. But the weather has gotten colder so we shall see what the summer brings. I'm using it much more now pulling my trailer so we shall see.

Thanks for every ones help.


#111

troy-built

troy-built

bertsmobile1 said:
Not some thing I wouldhave thought about with a mower, but the same applies spin at 1000 rpm and get a spark, spin at 400 rpm cranking speed and no stark.
Click to expand...
You are exactly correct. The battery needs to be fully charged I have also found out.


#112

Scrubcadet10

Scrubcadet10

You didn't take any "heat shielding" off the cylinder heads did you?


#113

troy-built

troy-built

Scrubcadet10 said:
You didn't take any "heat shielding" off the cylinder heads did you?
Click to expand...
Yes I did and it helped. Why shouldn't I have done that? To me it was just keeping the heat in. And yes I know the shielding helps the fan blow air across the fins. But when you turn the motor off they just hold heat in.

A little back info on this mower. I use it to pull a little trailer only the mowing deck is off of it so it doesn't run for hours at a time anymore.


#114

troy-built

troy-built

WOW 6K views of this thread. Hard starting must be a bigger problem than I thought.


#115

troy-built

troy-built

Scrubcadet10 said:
You didn't take any "heat shielding" off the cylinder heads did you?
Click to expand...
Yep, As far as taking the heat shielding off. I did an experiment, I ran the mower around for 15 min to make sure it was totally hot. I checked the temp of the heads with the shielding off and then I put the shielding back on. I turned the mower off with and without the shielding. I checked the temp of the heads. The heads were the same temp both times when the mower turned off. Then I checked them 15 min later with and without. The heads without the shielding was 25 degrees cooler than the ones with the shielding. So the shielding does hold the heat in just as I thought.
This mower blows so much air when running it blows leaves when I'm riding through the yard. So I'm not worried about it over heating I'm just glad it's starting every time now.


#116

Scrubcadet10

Scrubcadet10

Wow, interesting to find out...


#117

troy-built

troy-built

Scrubcadet10 said:
Wow, interesting to find out...
Click to expand...

I thought so myself.


#118

troy-built

troy-built

Yep that's where I often find mine.


#119

troy-built

troy-built

Ok I have an update. I've been running and using my mower a lot lately. Still from time to time it wouldn't start if it was hot and I have turned it off and on several times. I have found that if the battery isn't fully charged that would keep it from spinning fast enough to start it. But if I would let it cool off just a little lets say 15 min it would start right up.


#120

troy-built

troy-built

Yesterday I changed my 4 screw nikki carb to a 3 screw because it has more adjustments. What a difference it made, It runs and start like a totally different motor. I believe now it was getting to much fuel and that had a lot to do with it not starting properly. One thing it did before was backfire almost every time I turned the motor off when it was hot. That was caused by to much fuel on the hot piston I believe.

This has been a long process but I believe it is fixed now.

Hope this will help others.


#121

troy-built

troy-built

Ok, I do want to thank everyone again for all of there help along the way.
Here is an update on how my mower is starting now that it has gotten hot and into the mid 90s. I use my mower all the time now with my trailer behind it. That was one of the best things I could have done with it.
I know I have started it at least 300 times and it has yet to not start not even once. It starts right up.
Before I swapped out the carb it wouldn't start once or twice out of 20 times until it cooled down. So my conclusion is that it was the carb from the beginning. I did learn a lot along the way and I'm sure I have a way better tractor because of it. I guess it's a tractor now since I took the deck off of it. LOL

This will be my last post here unless something changes.

Have a great summer all.


#122

troy-built

troy-built

Since I'm here to ask a question I might as say one more thing about my mower. I also found out that as long as the battery is fully charged it starts much faster. So the carb and the battery was the best fix.


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