This may get a little long, but niece is having running issues with her 3 year old JD LA 145 with a 22hp twin. I have never had an engine do this before, but here goes;
It ran fine 2 weeks ago when we last used it, then the next time it did not want to start. Had to use starter fluid and when it did start, it ran very rough and would not accelerate. Black smoke began to come from exhaust and the fumes would burn your eyes and nose. It sounds like it is hitting about every other stroke or so and barely running fast enough to idle. So far, this is what we have tried and found out.
The coils, plugs, wires, are all good. It does not have a firing problem.
All the safety switches were checked and are working as they should.
This pretty much eliminates an electrical problem.
The carb was removed and thoroughly cleaned as well as the tank. The fuel pump is working as it should and we are convinced it is getting enough fuel.
The compression in both cylinders is 150 psi.
The valves are all working perfectly.
So, this is what I was able to observe.
The engine will start and run smooth initially...uhh sometimes. Sometimes it runs as mentioned above for a while, then begins to run smooth after a few minutes.
When the engine runs smooth, it can be accelerated slowly, but when it runs rough, it can not.
If I try to increase engine speed too fast, it will revert to running rough again.
If I engage the blades while it's running smooth, it begins to run rough again.
Seems that anytime there is a sudden engine acceleration, or a sudden load such when the electric clutch is activated, the engine will revert back to running rough.
Whenever the blade is engaged, or the accelerator is moved too rapidly toward high speed, the gov. lever drops completely and remains there until I either lift it by hand, or the engine is shut off. It is not binding as far as the action of the lever and rods. It's almost as if when the gov. lever falls too low, there is something keeping it there until it is forced up or the engine is shut down.
We have had 2 very knowledgeable lawnmower mechanics to check it out and both are scratching their heads right now. Is it possible that the gov. shaft from the engine has slipped within the lever and is out of adjustment? Is it possible for the gov to go so low that it actually is being held down by the forces of the engine? Both gov springs are connected.
It ran fine 2 weeks ago when we last used it, then the next time it did not want to start. Had to use starter fluid and when it did start, it ran very rough and would not accelerate. Black smoke began to come from exhaust and the fumes would burn your eyes and nose. It sounds like it is hitting about every other stroke or so and barely running fast enough to idle. So far, this is what we have tried and found out.
The coils, plugs, wires, are all good. It does not have a firing problem.
All the safety switches were checked and are working as they should.
This pretty much eliminates an electrical problem.
The carb was removed and thoroughly cleaned as well as the tank. The fuel pump is working as it should and we are convinced it is getting enough fuel.
The compression in both cylinders is 150 psi.
The valves are all working perfectly.
So, this is what I was able to observe.
The engine will start and run smooth initially...uhh sometimes. Sometimes it runs as mentioned above for a while, then begins to run smooth after a few minutes.
When the engine runs smooth, it can be accelerated slowly, but when it runs rough, it can not.
If I try to increase engine speed too fast, it will revert to running rough again.
If I engage the blades while it's running smooth, it begins to run rough again.
Seems that anytime there is a sudden engine acceleration, or a sudden load such when the electric clutch is activated, the engine will revert back to running rough.
Whenever the blade is engaged, or the accelerator is moved too rapidly toward high speed, the gov. lever drops completely and remains there until I either lift it by hand, or the engine is shut off. It is not binding as far as the action of the lever and rods. It's almost as if when the gov. lever falls too low, there is something keeping it there until it is forced up or the engine is shut down.
We have had 2 very knowledgeable lawnmower mechanics to check it out and both are scratching their heads right now. Is it possible that the gov. shaft from the engine has slipped within the lever and is out of adjustment? Is it possible for the gov to go so low that it actually is being held down by the forces of the engine? Both gov springs are connected.