Briggs & Stratton 18.5 Intek engine - pushing oil out fuel pump, dip stick...

[jpilk99]

Model # 31P777-0296E1

Engine starts right up, runs well, and has about 93psi compression. But after a minute or so, oil is coming out the vent hole of the fuel pump. Another time it spit back out through the dipstick tube.

Assumedly, I have pressure in the crankcase? Bad head gasket?

I thought it might be my valves so I set them, they're good. I've read some posts online that suggest Briggs Intek engines are somewhat notorious for this and that it's a blown head gasket. But if that were true, why would I have 93psi and why would pressure build in crankcase vs. dissipate out blown headgasket.

Stumped. Thanks for any help.

Jay

 

[tomplum]

Yes. The head gasket is the likely culprit and they will bleed from the pump vent some times. The gasket erodes away between the cylinder and the valve galley. They many times start out small, almost like you took the tip of a pencil and scraped a small path.

 

[jpilk99]

Yes. The head gasket is the likely culprit and they will bleed from the pump vent some times. The gasket erodes away between the cylinder and the valve galley. They many times start out small, almost like you took the tip of a pencil and scraped a small path.

Thanks Tomm (as always). I have the head gasket(s) and others coming - will report back.

 

[Willman]

Yes. The head gasket is the likely culprit and they will bleed from the pump vent some times. The gasket erodes away between the cylinder and the valve galley. They many times start out small, almost like you took the tip of a pencil and scraped a small path.

Yes. Tomplum is exactly right, I had a bad head gasket on the same engine, while the head is off check the valve guides and seats

 

[Richard001]

Yes. Tomplum is exactly right, I had a bad head gasket on the same engine, while the head is off check the valve guides and seats

You may also want to check the head for flatness. Use a heavy glass sheet, clean the head gasket surface and then put the head on the glass. Use a feeler gauge to check for any high spots on the head. Using an inspection light will also work.

If the mating surface of the head is not flat, put some sandpaper on a flat piece of metal and rub the head surface on it a bit. You will soon see and areas that the paper did not touch. Keep doing it until the entire head surface shows a pattern from the sandpaper.

 

[jpilk99]

UPDATE: Thanks so much, everyone. Headgasket, in that classic spot at 3:00 between piston and pushrod section. Cleaned everything up, new gasket with sealer, properly torqued, reset valves ...and NEW machine. 135psi!!!! Thank you.