Briggs & Stratton Engine Stalls After Running a While

[RDL90250]

I have a Briggs & Stratton Engine, model 123K02 engine. The engine starts fine and will run for about 1/2 hour or so but then starts to sputter, sometimes it "works" through initial sputtering but will eventually sputter again and stall out.

I have cleaned the carburetor, replaced the coil, replaced the breather, replaced the plug, replace head gasket all with no appreciable difference.

Any ideas as to what else I can look at?

Thanks,

Rick

 

[Scrubcadet10]

when it starts to sputter, loosen the gas cap and see if it will continue running.

 

[RDL90250]

when it starts to sputter, loosen the gas cap and see if it will continue running.

Did that no difference.