Outdoor Power Equipment and Small Engines - Question: Briggs 17hp Single

Hi -

My uncle gave me his lawnmowever b/c it was leaking oil everywhere and smoking while he mowed. I think I can fix it, but I need reassurance...

Problems:

Engine is pushing exhaust gas, oil smoke, and oil out the breather hose in the side of the crank case. I unhooked the breather hose from the air cleaner and stuffed the end in a bottle. I ran the mower for about 15 min and collected approx 10 ounces of oil in the bottle.

To me this suggests a that the piston rings are gone. I don' t have the equipment to do a compression test so I am not sure.

Other than smokey exhaust and oil consumption the mower seems to run fine.

Does anybody agree/disagree or have other suggestions?

Thanks!

You didn't give any engine numbers, so it'll be dificult to really know what engine this is. Start by smelling the oil. Does it smell like gas & is the level overfull?? thats a lot of oil to blow out. I suspect a float, needle & seat in the carb leaking & filling the crank with gas. If it has a fuel pump, the diaghpram may be leaking,too. Post the numbers & the pros will set you up with the right ideas. Good luck, Roger

Sorry, the B&S numbers are as follows:

Model - 311707
Series - 1032

The oil didn't smell like gas, and the oil level was slightly below full at the beginning of my test.

I should note that there is a significant amount of pressure being expelled out of the crank case breather hose. Shouldn't the crank case be operating in a slight vacuum??

Could it be a head gasket??

Thanks

Head gasket would be my guess. I'd pull the head and look at the gasket before going any further.

sounds like excessive crankcase pressure which can be bad compression rings or worn valve guides. Start pulling the head and looking at the cylinder walls and then when the valves are open, check the side travel. Sounds like a very worn engine and might be cheaper to get a replacement for a couple of hundred, depending on the manufacture of the orginal mower. Some of the cheaper ones, you can buy a replacement for the money you would put into the engine.

Well it was the head gasket. Pressure was bleeding through from the combustion chamber over into the pushrod channel. This caused excess pressure in the crank case resulting in oil spewing out the breather.

I think i may need to offer this free lawn mower back to my Uncle since it only cost me $11.00 to repair!

Thanks for the advise!