Hi,

I have a Briggs and Stratton 16HP flat head 180 v engine in a garden tractor. It has done lots of laps around the yard, over 25 seasons.

The engine is drowning its paper air filter in oil after only a week or so. Looks to me like the oil is getting coughed up from the throat of the carb, not the breather pipes. (will do it w/ breathers open to the air too). The engine will be choked out, and run very rich, and misfire/smoke.

If I run with out the air cleaner, it will run just fine! The misfire clears up as soon as it's removed. A new air cleaner is $17. I can't just keep replacing it weekly!

Do you think that the problem is worn valve guides, or bad valves? The oil level is normal, and I run the mono grade HD 30 as recommended by B&S for summer.

Can I get by with a thick oil, to slow the leak? Engine is loose and tired. Lots and lots of hours.


Thanks for your help,

Pete

It is probably a fuel oil mix, the only way for the crankcase oil to enter the air filter is through the breather tubes. Lapping the valves and setting the clearence will probably solve the problem. The intake is staying slightly open and causing some fuel mix to blow back into throat.

Don

Cool thanks.

A compression test would tell me more, and which cylinder is the leaker... Think I can lap those valves myself, or is that something I need to farm out to a machine shop? Do you think they need to be re-ground?

It is valve in block, so I can just pop the heads off and lap away...

I'll check compression, and I'll post the results.

Yeh, you could be getting blow by past the rings and that would be more through the crankcase breather. The fact it is coming in the throat tells me the valves are not seating.

You need to remove the valves and inspect the seat for burns, Briggs are notorious for the seats coming loose also so check those.

Get a repair manual it will help, and to adjust clearance you grind the end of the valve.

Don