B&S Pumping oil

[Robert]

Hello I have a 2000 bigfoot with an 18 hp Briggs and stratten and I just did an oil change set the valves and rebuilt the carb and now when I start it it seems to pump oil up the breather tube into the air cleaner the air cleaner was coated in oil after I took the air filter off . The air filter is new so it is not pluged
Please help
Thanks Rob

[Roger S]

Is it over full on the stick. You might be able to rinse the filter in solvent and save it, if it's soaked.

[Robert]

Thanks for getting back I checked the stick and it is at half on the stick I took the oil fill cap off and i can feel air pulsing out of the hole when it is idleing , it didnt do this before i started the tune up also I used synthetic oil in the oil change and set the valves to 4 thou for each side

[Roger S]

It's normal to have crankcase pressure pulsing.. as both pistons move up and down somewhat together. I don't have any other clues why it just started..

Not that it's related, but the piston is supposed to be a 1/4" down the bore past TDC to ensure the compression release is not interfering with valve adjustment..

[wfo]

How does the engine run...with cap off does it pulse just air or is their
blue smoke, when hot

[Roger S]

It won't run very long with the cap off, only until the carb bowl runs dry. The oil fill and dipstick have to be air tight, otherwise the pulse fuel pump won't work. It will throw oil out any opening when running.

There's some reasons for it to push oil out the breather tube, but the way you worded your post, I assumed it just started doing this after the oil change.. or do ya think you just started noticing a long term problem.

[Robert]

Thanks for replying everyone,I found the problem ,when I did the valve adjustment one of the valve cover gaskets was not in sitting properly and was leaking air into the crankcase causing a positive pressure in stead of a negative pressure .I fixed the gasket and problem solved.
thanks again for your help
Rob

[hydromike]

Isn't it great to find such easy fixes?

Glad you have it figured out. I've locked this little bit into my memory banks if the issue ever arises.

[waylonh]

Had the same thing happen. I loaded my gaskets up with bluegasket maker just incase. No more puking!