Craftsman GT6000 runs 5min and backfires and stalls. Won't restart.

[gentlecowboy]

My Craftsman with a 18hp Kohler twin won't start. when I finally get it started it runs 5 minutes, the it sound like one cylinder quits. It then backfire and stalls. Won't restart. I smell gas. Pull plugs. One soaked with gas, one bone dry. Tried new plugs. If I let it sit overnight, it repeats the same scenario. Frustrated. Is the magneto failing?

 

[Rivets]

Could be a coil failing, but I suspect that carb work is going to be needed. Next time it happens check for spark on both cylinders. If one has no spark, probably bad coil. If both have spark, it will probably be a fuel problem and I would start with rebuilding the carb and changing the intake gaskets.

 

[EngineMan]

My Craftsman with a 18hp Kohler twin won't start. when I finally get it started it runs 5 minutes, the it sound like one cylinder quits. It then backfire and stalls. Won't restart. I smell gas. Pull plugs. One soaked with gas, one bone dry. Tried new plugs. If I let it sit overnight, it repeats the same scenario. Frustrated. Is the magneto failing?

I would look at the cylinder that was wet...! and check the coil next time it goes down.

 

[tankdriver]

Since it is always one cylinder, I'd look and see if there is a valve sticking open when it quits. You can try some Sea Foan. If it is just a build up of crode on the stem, that should take care of it.

Hopefully it is not a bent stem.