sail902
New member
I have a 2009 JD LA145 with a Briggs 22hp mod. 407777 engine. 190 hours
All started with surging at idle and cranking too long to get started especially when it sat for a couple days. It also smells rich when running and pops through the carb sometimes.
Rebuilt the carburator, new plugs,fuel filter,air filter, oil change and no help. Tore down the carburator again and checked everthing and still no change. Adjusted the valves and the governor and still no change.
Went to pull the plugs after the mower had been running for about 5 min. and noticed that the plug and the valve cover on the right cylinder (as you sit on the mower) was much hotter than the left side. I could not keep my hand on the right valve cover or plug at all but i could leave my hand on the left side cover and plug.That told me that the left cylinder was not working very well.
I was getting spark and fuel, so that promped me to check compression and it was good except it was a little higher on the left cylinder (cold side). I thought maybe the valves on the left side were not opening enough, so I checked the valve clearance again and they were at about .070, so I set them at .040 using method I saw on youtube where you rotate the engine until one valve is all the way open and you adjust the other one as it's all the way closed etc. It was very tricky to get it just right at .040. After I got the valves just right I started again and still same problems, but seemed even worse.
Not sure where to go from here... I did notice on the old original plugs that I took out that one looked older and more used (had gotten hotter) than the other one where the porcelin at the base of the electrode was brighter (more white) So this must have been going on for quite a while. The mower seemes to have good power at full throttle and mowes ok, but maybe I have never seen the full potential sinch this has probably been going on the whole time. The mower was bought from lowes as reconditiond. I guess it had been returned and sent back to the John Deer dealer and they put a new carburator on it. When i got home, it wasn't running right so I brought it back to the JD dealer and they fixed it under warranty and they did something with the carburator. I got it back home and it still wan't running right so I brought it back and they said that the intake manifold was leaking and they resealed it. (turns out that they didn't replace round rubber gaskets, they just put some goop on them as well as the valve cover gaskets-- it was a mess and I found this when I rebuilt the carb.) It ran better so I figured that it was ok for a while
The only next move that I can think of is to swap the magnitos from one cylinder to the other and see if the bad cylinder moves with the magnitos. The spark was good on both sides, I tested with a good extra plug that I had that I had pulled the electrode back to make a large gap for the spark to jump and it seemed fine.
So I'm at a total loss here.... what am I missing or what else could it be??
I'm not sure how accurate my compression gauge is, but that both cylinders are within 5 pounds with the bad cylinder having the higher reading. I haven't been able to find many specs on this engine and when I do, I get different specs from different sites. All I got is intake and exhaust valve clearance is .040 or .050, spark plug gap at .30. I see no carburator adjustments at all except for idle speed screw. not even a float adjustment. Anyone know where I can get all the right specs for this engine? JD and briggs sites don't have.
Thanks for reading, any thoughts, ideas, or tell me where I'm going wrong would be appreciated!
All started with surging at idle and cranking too long to get started especially when it sat for a couple days. It also smells rich when running and pops through the carb sometimes.
Rebuilt the carburator, new plugs,fuel filter,air filter, oil change and no help. Tore down the carburator again and checked everthing and still no change. Adjusted the valves and the governor and still no change.
Went to pull the plugs after the mower had been running for about 5 min. and noticed that the plug and the valve cover on the right cylinder (as you sit on the mower) was much hotter than the left side. I could not keep my hand on the right valve cover or plug at all but i could leave my hand on the left side cover and plug.That told me that the left cylinder was not working very well.
I was getting spark and fuel, so that promped me to check compression and it was good except it was a little higher on the left cylinder (cold side). I thought maybe the valves on the left side were not opening enough, so I checked the valve clearance again and they were at about .070, so I set them at .040 using method I saw on youtube where you rotate the engine until one valve is all the way open and you adjust the other one as it's all the way closed etc. It was very tricky to get it just right at .040. After I got the valves just right I started again and still same problems, but seemed even worse.
Not sure where to go from here... I did notice on the old original plugs that I took out that one looked older and more used (had gotten hotter) than the other one where the porcelin at the base of the electrode was brighter (more white) So this must have been going on for quite a while. The mower seemes to have good power at full throttle and mowes ok, but maybe I have never seen the full potential sinch this has probably been going on the whole time. The mower was bought from lowes as reconditiond. I guess it had been returned and sent back to the John Deer dealer and they put a new carburator on it. When i got home, it wasn't running right so I brought it back to the JD dealer and they fixed it under warranty and they did something with the carburator. I got it back home and it still wan't running right so I brought it back and they said that the intake manifold was leaking and they resealed it. (turns out that they didn't replace round rubber gaskets, they just put some goop on them as well as the valve cover gaskets-- it was a mess and I found this when I rebuilt the carb.) It ran better so I figured that it was ok for a while
The only next move that I can think of is to swap the magnitos from one cylinder to the other and see if the bad cylinder moves with the magnitos. The spark was good on both sides, I tested with a good extra plug that I had that I had pulled the electrode back to make a large gap for the spark to jump and it seemed fine.
So I'm at a total loss here.... what am I missing or what else could it be??
I'm not sure how accurate my compression gauge is, but that both cylinders are within 5 pounds with the bad cylinder having the higher reading. I haven't been able to find many specs on this engine and when I do, I get different specs from different sites. All I got is intake and exhaust valve clearance is .040 or .050, spark plug gap at .30. I see no carburator adjustments at all except for idle speed screw. not even a float adjustment. Anyone know where I can get all the right specs for this engine? JD and briggs sites don't have.
Thanks for reading, any thoughts, ideas, or tell me where I'm going wrong would be appreciated!