[thecayub]

Hello everyone, this is my first post on this site. My issue today is this:

I have a 38" simplicity with a 15.5hp briggs single cylinder ohv engine. The problem it has is that it burns oil/gas. There is gas in the oil as well. I researched this and several people said the carb was trashed and needed rebuilt, so, I installed a brand new one. This has still not solved the problem. I popped the head off, replaced the head gasket, adjusted the valves, and compression tested it (110lbs). It still burns a lot of blue smoke from the exhaust, as well as the crank case breather that leads into the airbox. Any ideas what to do now? Thanks!!

 

[Austen]

:welcome: to MLMF!

From what you describe and have already done, it sounds like the piston rings are worn and that it's getting blow by. Typically this is a sign of a well used engine that could use a rebuild.

If you plan to continue using the machine as-is you can try running a slightly thicker oil although I wouldn't go too overboard with a much thicker viscosity.

 

[thecayub]

Alright thanks! Worn rings even with 110psi on the compression test?

 

[Austen]

The compression does sound on the high end, but from you describe at least it points to the rings imo.

Perhaps others will chime in with some other ideas.

 

[Brad]

have you checked to see if there is gas flowing into the carb when the engine is not running? Do you have a fuel shut-off installed?

 

[Mark / Ohio]

Another point of entry for gas getting into the crankcase could be a vacuum operated fuel pump if it is so equipped.

 

[thecayub]

I have checke for gas overflow and theres no problems there. Just changed the oil and there was a lot of gas in it, it smokes like a banshee when under a load (pto engaged) but doesn't smoke when just idling

 

[rub87ST]

Alright thanks! Worn rings even with 110psi on the compression test?