OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines Oil leak from Fuel Pump

I only seem to post 'curly' questions and this one is no exception.
21B877 engine with oil leaking from Fuel Pump breather.

The fault is NOT caused by any of the following (in order of probability):

Excessive Oil in case
Blocked breather tube / box
Blown Head Gasket
Leaking seals / gaskets etc

Leakdown test shows a typical "used" engine, so yes there is a small amount of blow by and barely detectable valve leakage (at 130 psi).

If you can't think of a solution, don't feel bad, as B&S technical are also starting to scratch their heads. Only think I have not done so far is peak pressure oscillation (case vacuum), but it seems pointless as baseline specs for this engine are not available.

Any thoughts from the guru brigade?

Doesn't the crankcase-pulse operated fuel pump on those Inteks attach to the dipstick tube? I seem to recall the pumps are quite prone to wearing out, and dripping oil (there is plenty of oil mist and splashes included in those crankcase pulses). If my guess is right, you need a new fuel pump.

Hi grumpy, close, but no cigar. Pump passes test and I should have put that in my original post....my bad.

I, and I think the Outdoorking archives, have only one previous report of a fault similar this and from memory, we didn't ever reach a resolution - we were mainly focused on excessive crankcase pressure and were tending to blame that on either leaky headgasket or leaky rings. However, one thing I didn't think of at the time but seems a plausible cause: are you sure the Positive Crankcase Ventilation valve is not stuck closed or obstructed? If so, the fuel pump might leak before the engine gaskets did. I note you've said you've checked the breather tube and "box", but I'm not sure you've checked the valve.