YANMAR Trouble

JonSpinosa · Feb 12, 2001

Hi guys, I have a question for you mechanics. I have a John Deere F932 with a 3 cylinder Yammar gas engine. Sometimes when I start the engine it sounds and feels like it is not running on all 3 cylinders and seems like it is not firing properly. When I rev up the engine you can just hear and feel that it is running rough. However, it does not do it all the time. It seems like every other time I run the engine it does this. I did change the plugs and it seemed to help for awhile. Sometimes it can smell funny as if the combustion process was not right. Do you guys have any thoughts. Thanks for your help!

willsonlj · Feb 12, 2001

I used to have a Japanese motorcycle that did what you are describing. The problem turned out to be a bad ignition coil wire. Just a thought.

Muhammad · Feb 13, 2001

Did you check the fuel injectors, fuel line and fuel quality yet? Ever run it out of fuel?

Just some initial thoughts...

Thomas · Feb 13, 2001

Have you change the fuel filter,also start w/ fresh fuel.

Thomas..NH /w3tcompact/icons/wink.gif

DFB · Feb 13, 2001

In my Deere manual under the heading of Uneven Combustion Sound/Troubleshooting the causes listed are as follows:

Fuel -water
Fuel -wrong type
Fuel Injectors-uneven volume
Fuel Injectors-poor pattern
Clogged or Leaking Air Filter
Clogged Exhaust Pipe

Sounds like your heading down the right track here.

DFB

JonSpinosa · Feb 19, 2001

Thanks for the help guys. I suspected it to be something in the ignition system so I decided to purchase 3 new coils with spark plug wires and it solved the problem. The Yanmar 3 cylinder gas engines each have a coil with an attached spark plug wire. I decided to purchase each coil at a price of $35.00 per coil and plug wire. I suspected it to be one of those coils but did not know how to test each coil. I just figured buying all three would still be cheaper than taking it to a dealer. Thanks for your help.

markcg2000 · Feb 20, 2001

Good move, buying all three. You just know that the second one will fail right after you get the machine running again /w3tcompact/icons/tongue.gif.

mark

JATO_RaT · Feb 21, 2001

I know it's moot at this point, but could you not remove each wire from the plug and do a visual check of the spark intensity to ground? Perhaps there is more to it though. With a digital ohm meter you can also check the resistance in the wires. Knowing what the resistance is can be confusing but a rule of thumb would be to check that the values are relatively close. This would be a guide provided not all the wires are bad. Of course, now that you have all new wires and coils, you are pretty well set and should be trouble free for some time. Rat...