Kawasaki 691 requires full choke only when warmed up ?

[dannyboy44]

I am lost on this one. I have a Gravely with the FS691 engine. After running for anywhere from 10 minutes to say 30 minutes the engine starts to surge or stutter. If i put on full choke it is better for a short time but eventually I need to limp back to the garage.

I have changed the plugs, fuel filter, air filter, coils, put in fresh gas and added some Lucas injection cleaner to the gas thinking this may clear out the jets if that is the issue.

No improvement after the above work was done. The fact that I need full choke suggests to me that there is a fuel delivery issue so I need to enrich to keep it running, correct?

The reason I changed out the coils was I thought maybe when the engine heated up it effects one of the coils. I would think if the problem is fuel delivery it would require the choke even when engine is cold.

Any thoughts on why full choke required on a hot engine

 

[sgkent]

anything that changes the air to fuel mixture. You've picked the low hanging fruit. Next is looking for intake leaks, and head leaks. Even a tight valve can change the mixture.

 

[txmowman]

Full choke to restart a hot engine is normal. If full choke is needed to keep it running, this is a fuel delivery issue. You would need to check the entire fuel system from tank to carburetor. Possibly a fuel cap not venting. When it starts to surge, open the cap. Other tank venting issue or a possible air leak on the carb mounting gasket or intake manifold.

 

[bertsmobile1]

Classic floating debris in the fuel tank blocking off the outlet or bad fuel line blocking off the fuel supply
When it stops, pull the fuel line off and blow bak through the tank
If it is hard then goes easy and the surging goes away for a while then that confirms fuel starvation.
Do that and get back with the result .