Briggs Lhead Twin Compression

[davbell22602]

Does anybody know the compression spec is on 18hp Lhead twin Briggs, 422437,1209-01, 1988 model?

Tested left cylinder at 30-40 but peaked 60 once. Tested right cylinder at 60-70 but peaked 90 once. I guess its time for rebuild.

 

[EngineMan]

Does anybody know the compression spec is on 18hp Lhead twin Briggs, 422437,1209-01, 1988 model?

Tested left cylinder at 30-40 but peaked 60 once. Tested right cylinder at 60-70 but peaked 90 once. I guess its time for rebuild.

B&S don't give compression spec's, left cylinder is low you should be looking for something above 60psi 90psi or above would be much better, but 90psi is OK, check the valves, re-lap and re-set them and check head gasket, rings would be the last to check, signs will be there when you take off the head.
Intake .004-.006
Exhaust .007-.009
Cylinder Head 160in.Lbs

 

[reynoldston]

I agree with engineman check valves, but before anything check valve adjustment.

 

[Rivets]

A simple test now would be to squirt a small amount of engine oil into each cylinder. If the compression goes up, it is a indication that the rings will need to be replaced.