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Briggs and Stratton 300E surging bad
#1
B
banjomaniac
B
banjomaniac
I bought this Murray mower for a friend who is kind of down on their luck thinking I could put a blade on it and have them a good mower but it's surging really bad. I can watch the governor moving back and forth so I pulled the carburetor apart 3 times cleaning it very well I did not use carb cleaner because it's plastic but I pulled the plastic jet tube out everything looks really good in this carburetor. Put it back together and its still surging. I can hold the governor arm slightly in and it runs nice and smooth spring looks good on the governor but I was wondering if I just put a heavier spring on if it would hurt anything? Now this mower doesn't have a blade on it right now I also wondered if just not having the blade can cause this to run this way?
Banjomaniac
Banjomaniac
#2
S
shiftsuper175607
Look below at Similar Threads for a reply on the same problem of same engine.
S
shiftsuper175607
I bought this Murray mower for a friend who is kind of down on their luck thinking I could put a blade on it and have them a good mower but it's surging really bad. I can watch the governor moving back and forth so I pulled the carburetor apart 3 times cleaning it very well I did not use carb cleaner because it's plastic but I pulled the plastic jet tube out everything looks really good in this carburetor. Put it back together and its still surging. I can hold the governor arm slightly in and it runs nice and smooth spring looks good on the governor but I was wondering if I just put a heavier spring on if it would hurt anything? Now this mower doesn't have a blade on it right now I also wondered if just not having the blade can cause this to run this way?
Banjomaniac
Look below at Similar Threads for a reply on the same problem of same engine.
#3
Boudreaux In Eunice La.
Boudreaux In Eunice La.
Your carb is still not cleaned all the way..........
Here's a video link ..... https://youtu.be/_5PBMOZLclQ
You can skip the skit and go to the 4:00 mark if you want...........
Here's a video link ..... https://youtu.be/_5PBMOZLclQ
You can skip the skit and go to the 4:00 mark if you want...........
#4
B
banjomaniac
B
banjomaniac
I've had it apart 4 times, followed the video and even popped out that tiny steel ball, this carb is clean ask new. I ran the wire through all the Jets and even used a magnifying glass to look, it is clean. It looked good the first time I took it apart. The gasket looks good, o ring is there. I watched several videos on cleaning this carb but still surges. Only thing I can figure is it has a vacuum leak or down inside carb base where you can't see or get to has a blockage but I really doubt it. I give up.
#5
Boudreaux In Eunice La.
Boudreaux In Eunice La.
Ok the next thing would be to give the governor spring a good look over........ They break very easily..... I keep 4 or 5 in stock all the time.....
The spring will be on the under side... Not on the top side like older style engines.... If the spring is broke it will surge....
OR the guy you got it it from disconnected the governor arm from the engine...... Or it could be a fuel line gone bad on the inside of it.....
Fuel lines go bad all the time, and there is no way of checking them by blowing thru them.......
The spring will be on the under side... Not on the top side like older style engines.... If the spring is broke it will surge....
OR the guy you got it it from disconnected the governor arm from the engine...... Or it could be a fuel line gone bad on the inside of it.....
Fuel lines go bad all the time, and there is no way of checking them by blowing thru them.......
#6
B
bertsmobile1
B
bertsmobile1
There is a short manifold that the carb mounts on to.
It is held on by the bracket the card sits in and seals via an O ring.
So take it off and check the O ring for damage.\People who are not familar with these carbs regularly loosen off these screws but fail to tighten them or allow debris to fall under the O ring when removing or replacing the carb.
It is part 122 ( O ring + manifold ) in this diagram https://www.jackssmallengines.com/jacks-parts-lookup/manufacturer/briggs-stratton/020000-09z999-series/08p500-to-08p599/08p502-0003-h1/carburetor
Also check the o ring between the carb & the manifold part 617 for nicks that can be leaking air.
Two side to surging
not enough fuel
too much air.
So air entering after the right amout of fuel has been added will also cause surging.
The O rings are cheap so I like to replace them regardless a belts & braces fix.
It is held on by the bracket the card sits in and seals via an O ring.
So take it off and check the O ring for damage.\People who are not familar with these carbs regularly loosen off these screws but fail to tighten them or allow debris to fall under the O ring when removing or replacing the carb.
It is part 122 ( O ring + manifold ) in this diagram https://www.jackssmallengines.com/jacks-parts-lookup/manufacturer/briggs-stratton/020000-09z999-series/08p500-to-08p599/08p502-0003-h1/carburetor
Also check the o ring between the carb & the manifold part 617 for nicks that can be leaking air.
Two side to surging
not enough fuel
too much air.
So air entering after the right amout of fuel has been added will also cause surging.
The O rings are cheap so I like to replace them regardless a belts & braces fix.
#7
B
banjomaniac
B
banjomaniac
I had the carb Bowl off this last time I went ahead and connect to the fuel line and manually work the float gas runs out at a pretty good rate so I don't think there's a problem with the fuel line also the O-ring and plastic keeper are there I made sure to snap them back in the carburetor and the gasket on the underside of the carburetor where it meets the intake looks good I'm at a loss to governor spring is in good condition I actually tried shortening it a hair to see if it would help the arm is connected only thing I can think is down in the bottom of the carburetor when you slide the plastic tube down in there that has the Jets that bottom part of the carburetor may have something in it but I sure can't see it I shined a flashlight use the magnifying glass.
#8
B
Boit4852
B
Boit4852
From the original post, you state that you are running the engine without blades. Blades add inertia to the engine which smooths out the engine mostly at low RPM. Install blades and see if that corrects your issue.It's not surprising that without blades installed that you would experience engine surging issues.
#9
B
banjomaniac
B
banjomaniac
Put a new blade on and it runs perfect, it didnt have a blade when I bought it and I was going to give it to a friend in need so I didn't want to buy a blade if it didn't run right I should have known better which is why I asked in my first post if that might cause this problem now everybody knows if it's set up to run with a blade it might run bad without one. Thanks for all the help.
ROW FASTER, I HEAR BANJOS!
Banjpmaniac
ROW FASTER, I HEAR BANJOS!
Banjpmaniac
From the original post, you state that you are running the engine without blades. Blades add inertia to the engine which smooths out the engine mostly at low RPM. Install blades and see if that corrects your issue.It's not surprising that without blades installed that you would experience engine surging issues.
#10
Boudreaux In Eunice La.
Boudreaux In Eunice La.
I thought I said in my first post too put a blade on it...... I guess my edit didn't go thru.......
Glad you got it going,,,,,, Now remember that newer style engine has small jets and does NOT like ethonal gas at all....
Plus Tard Mon Ami ~!~!
Glad you got it going,,,,,, Now remember that newer style engine has small jets and does NOT like ethonal gas at all....
Plus Tard Mon Ami ~!~!
#11
B
Boit4852
That's right. Ethanol spiked gasoline is killing so many small engines far prematurely. Maybe in the not so distant future, our incredibly stupid and corrupt politicians will rescind the ethanol requirements, but I'm not holding my breath.
B
Boit4852
I thought I said in my first post too put a blade on it...... I guess my edit didn't go thru.......
Glad you got it going,,,,,, Now remember that newer style engine has small jets and does NOT like ethonal gas at all....
Plus Tard Mon Ami ~!~!
That's right. Ethanol spiked gasoline is killing so many small engines far prematurely. Maybe in the not so distant future, our incredibly stupid and corrupt politicians will rescind the ethanol requirements, but I'm not holding my breath.
#12
A
asdunbar90
A
asdunbar90
I have a similar problem with my Briggs 08P502 005 F1. Part of the same 300e family, model series 080000.
It's on my MTD 11A-02BT729.
Constant surging.
Blade is intact and installed on mower.
What I've done so far:
Cleaned air filter.
Switched out gas.
Rebuilt carb completely, no clogs or debris present.
Checked O-rings/gaskets for cracks, none present.
Adjusted governor.
Checked gas tank air intake port, clear.
Checked gas line, clear.
Changed length of governor spring by slightly bending attachment arm on static end, results in faster or slower RPM, but still surging.
I'm out of ideas.
One thing I can admit. The first time the mower was used it was used on heavy tall grass. I'm wondering if I "broke-in" the mower under a heavier load than I use it at now.
Would this have stretched the governor spring or somehow set the mower to expect a heavier load?
I can hold the gov static and itll run great but as soon as I let go it'll slowely start surging and then pick up to rull sin wave surge mode. To the point where if I'm mowing I'll get patches of uncut grass hah!
It's on my MTD 11A-02BT729.
Constant surging.
Blade is intact and installed on mower.
What I've done so far:
Cleaned air filter.
Switched out gas.
Rebuilt carb completely, no clogs or debris present.
Checked O-rings/gaskets for cracks, none present.
Adjusted governor.
Checked gas tank air intake port, clear.
Checked gas line, clear.
Changed length of governor spring by slightly bending attachment arm on static end, results in faster or slower RPM, but still surging.
I'm out of ideas.
One thing I can admit. The first time the mower was used it was used on heavy tall grass. I'm wondering if I "broke-in" the mower under a heavier load than I use it at now.
Would this have stretched the governor spring or somehow set the mower to expect a heavier load?
I can hold the gov static and itll run great but as soon as I let go it'll slowely start surging and then pick up to rull sin wave surge mode. To the point where if I'm mowing I'll get patches of uncut grass hah!
#13
B
Boit4852
Here is what I would do if I was you. I'll skip over the the things you've already done to solve the issue. Take a short length of 10 or 12 AWG wire about 5 or 6 inches long and strip both ends back about 3/8' or so, twist the strands as tight as you can with your fingers and try to flatten those ends by squeezing with your fingers. Now, flip your seat up and disconnect the safety switch under the seat. It's a simple two-wire connector. With the connector apart, insert you custom made wire into the slots of the switch that have the two wires from your electrical supply. This will defeat the interlock and will allow you to run the engine with blades engaged without you needing to be on the seat. From here, run the mower with the blade drive engaged and observe the governor linkage with the throttle at about 50% You should be able to see if the spring is too weak or if the cable housing clamps are not adjusted correctly. Also, with the engine not running, observe the cables as you move the throttle and choke cables from idle to about 1/2 throttle. Make sure the choke cable is opening the choke once you move the throttle cable to run from idle to full throttle. My mower has separate choke/throttle cables so what I described does not apply, but, the engine (Kawasaki) is still sensitive to the the cable housing adjustment in the clamps. BTW, the jumper wire I've described is now permanent on my Exmark. I have no steep hills to be concerned about so I don;t need this safety interlock. Not only is this wire mod handy, it has helped me adjust my cables for spot-on throttle response and very accurate governor control. If you operate your mower on steep hills, remove the jumper wire after you've done your troubleshooting.
B
Boit4852
I have a similar problem with my Briggs 08P502 005 F1. Part of the same 300e family, model series 080000.
It's on my MTD 11A-02BT729.
Constant surging.
Blade is intact and installed on mower.
What I've done so far:
Cleaned air filter.
Switched out gas.
Rebuilt carb completely, no clogs or debris present.
Checked O-rings/gaskets for cracks, none present.
Adjusted governor.
Checked gas tank air intake port, clear.
Checked gas line, clear.
Changed length of governor spring by slightly bending attachment arm on static end, results in faster or slower RPM, but still surging.
I'm out of ideas.
One thing I can admit. The first time the mower was used it was used on heavy tall grass. I'm wondering if I "broke-in" the mower under a heavier load than I use it at now.
Would this have stretched the governor spring or somehow set the mower to expect a heavier load?
I can hold the gov static and itll run great but as soon as I let go it'll slowely start surging and then pick up to rull sin wave surge mode. To the point where if I'm mowing I'll get patches of uncut grass hah!
Here is what I would do if I was you. I'll skip over the the things you've already done to solve the issue. Take a short length of 10 or 12 AWG wire about 5 or 6 inches long and strip both ends back about 3/8' or so, twist the strands as tight as you can with your fingers and try to flatten those ends by squeezing with your fingers. Now, flip your seat up and disconnect the safety switch under the seat. It's a simple two-wire connector. With the connector apart, insert you custom made wire into the slots of the switch that have the two wires from your electrical supply. This will defeat the interlock and will allow you to run the engine with blades engaged without you needing to be on the seat. From here, run the mower with the blade drive engaged and observe the governor linkage with the throttle at about 50% You should be able to see if the spring is too weak or if the cable housing clamps are not adjusted correctly. Also, with the engine not running, observe the cables as you move the throttle and choke cables from idle to about 1/2 throttle. Make sure the choke cable is opening the choke once you move the throttle cable to run from idle to full throttle. My mower has separate choke/throttle cables so what I described does not apply, but, the engine (Kawasaki) is still sensitive to the the cable housing adjustment in the clamps. BTW, the jumper wire I've described is now permanent on my Exmark. I have no steep hills to be concerned about so I don;t need this safety interlock. Not only is this wire mod handy, it has helped me adjust my cables for spot-on throttle response and very accurate governor control. If you operate your mower on steep hills, remove the jumper wire after you've done your troubleshooting.
#14
B
bertsmobile1
One of the reasons why we ask people to post their engine and mower numbers is so when we do not know what they are having trouble with we can look it up.
MTD 11A-anything is a push mower
B & S 08P502 005 F1 is an 8 cube" engine, a bit small for a ride up unless your name is Stiga.
B
bertsmobile1
Here is what I would do if I was you. I'll skip over the the things you've already done to solve the issue. Take a short length of 10 or 12 AWG wire about 5 or 6 inches long and strip both ends back about 3/8' or so, twist the strands as tight as you can with your fingers and try to flatten those ends by squeezing with your fingers. Now, flip your seat up and disconnect the safety switch under the seat. It's a simple two-wire connector. With the connector apart, insert you custom made wire into the slots of the switch that have the two wires from your electrical supply. This will defeat the interlock and will allow you to run the engine with blades engaged without you needing to be on the seat. From here, run the mower with the blade drive engaged and observe the governor linkage with the throttle at about 50% You should be able to see if the spring is too weak or if the cable housing clamps are not adjusted correctly. Also, with the engine not running, observe the cables as you move the throttle and choke cables from idle to about 1/2 throttle. Make sure the choke cable is opening the choke once you move the throttle cable to run from idle to full throttle. My mower has separate choke/throttle cables so what I described does not apply, but, the engine (Kawasaki) is still sensitive to the the cable housing adjustment in the clamps. BTW, the jumper wire I've described is now permanent on my Exmark. I have no steep hills to be concerned about so I don;t need this safety interlock. Not only is this wire mod handy, it has helped me adjust my cables for spot-on throttle response and very accurate governor control. If you operate your mower on steep hills, remove the jumper wire after you've done your troubleshooting.
One of the reasons why we ask people to post their engine and mower numbers is so when we do not know what they are having trouble with we can look it up.
MTD 11A-anything is a push mower
B & S 08P502 005 F1 is an 8 cube" engine, a bit small for a ride up unless your name is Stiga.
#15
B
Boit4852
I jumped the gun about this not being a rider. However, as I described about jumping the seat switch is still valid in my opinion. If you have steep hills or ditches, I wouldn't leave this jumper wire in place.
B
Boit4852
One of the reasons why we ask people to post their engine and mower numbers is so when we do not know what they are having trouble with we can look it up.
MTD 11A-anything is a push mower
B & S 08P502 005 F1 is an 8 cube" engine, a bit small for a ride up unless your name is Stiga.
I jumped the gun about this not being a rider. However, as I described about jumping the seat switch is still valid in my opinion. If you have steep hills or ditches, I wouldn't leave this jumper wire in place.