I have a Kohler Magnum M18QS engine, probably from the early 90's which is installed in a Bobcat 440B loader. The engine will start (sometimes) and run, but will eventually die. Sometimes it'll run for 30 minutes or more and dies, other times it'll run for 5 minutes then die. Once it dies, it's near impossible to restart. Give it a day or so and it'll start up only to repeat all this crud again.
We checked for spark early on when it wouldn't start, and it didn't have spark. It didn't appear to be the grounding/kill wire, so we bought a new coil. Today I installed the new coil, but nothing. It had spark, but the engine would not start. I installed the old coil and it fired right up. So I installed the new coil again, and it wouldn't start....so I installed the old coil again and it fired right up. I suppose the new coil isn't good?
Anyhow, I put it all together again and started it up. It ran for no more than 5 minutes and died. I haven't been able to start it since, but it has spark. I removed the carburetor to check the fuel bowl - it was full of fuel, so I assume the fuel pump is working. Since I had the carburetor removed, I went ahead and cleaned the carburetor. I reinstalled....and nothing happens.
I'm lost at this point. This should be an easy engine to diagnose, but I can't seem to pinpoint what's wrong.
Any ideas?
We checked for spark early on when it wouldn't start, and it didn't have spark. It didn't appear to be the grounding/kill wire, so we bought a new coil. Today I installed the new coil, but nothing. It had spark, but the engine would not start. I installed the old coil and it fired right up. So I installed the new coil again, and it wouldn't start....so I installed the old coil again and it fired right up. I suppose the new coil isn't good?
Anyhow, I put it all together again and started it up. It ran for no more than 5 minutes and died. I haven't been able to start it since, but it has spark. I removed the carburetor to check the fuel bowl - it was full of fuel, so I assume the fuel pump is working. Since I had the carburetor removed, I went ahead and cleaned the carburetor. I reinstalled....and nothing happens.
I'm lost at this point. This should be an easy engine to diagnose, but I can't seem to pinpoint what's wrong.
Any ideas?