OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines Briggs & Stratton Fuel pump leaking oil

Hi Pinelli, welcome to Outdoorking.

Please post the Model, Type and Code numbers for your new Briggs. These numbers have traditionally been stamped on the cooling air cowl, but may be somewhere else on a new Briggs. The whole series of numbers will be together in a group. Some pictures of the engine, including the problem area, would also be very helpful.

If the engine is new, the first port of call for both problems (leaking oil, and hunting) should be the dealer you bought it from, since it should be under warranty.

So far as the oil leak from the fuel pump area is concerned, I won't comment until I see the pictures. I'm used to Briggs 12 hp engines being side-valve with gravity fuel feed. At this point I don't know whether yours is side valve, or a Vanguard, or an Intek.

The cyclic speed variation you have described sounds like "hunting", which is nearly always caused by lean mixture, though it can be due to mechanical friction in the governor mechanism, such as a governor link rubbing against some other part of the engine. However because you obviously have a fuel pump malfunction, I suspect the two problems are linked: the fuel pump may not be delivering enough fuel. Anyway, let's see the pictures and check out the engine model - then we'll talk about it from there.

One reason why we need the model information is that if it turns out your engine is an Intek, there is a good chance that it has a blown head gasket like so many other Inteks. This could be pressurising the crankcase, which is connected to the fuel pump diaphragm by the vacuum pulse hose that operates the fuel pump. With positive pressure on the diaphragm, the pump will not work well, and with pressure in the crankcase, there is likely to be air and oil coming through the pulse hose rather than just air.