I'm At A Loss!!!

[RevB]

Ok. I think I've isolated the area where the leak is coming from. It's either coming from the brass looking circle on the fuel pump or the little slot holes that go all around the pump. It's a brand new fuel pump but could it be bad too?

The brass circle is a sintered bronze air filter.

 

[Gord Baker]

The breather hose looks fine. I took it off and inspected it.

Is there a Crankcase Vent that may be plugged? Oil overfilled?

 

[jetsticks]

Guy, can you see tiny holes in a black rubber hose? It needs to be pressure tested maybe shooting soapy water at it.

"Looking" at most mower parts doesn't cut it for a true test.

I can't see any holes. I put it in a bucket of water and blew air into it and I got no bubbles. I'm pretty sure it's coming from the pump itself.

 

[jetsticks]

Is there a Crankcase Vent that may be plugged? Oil overfilled?

I don't believe so but I will check. Thanks.

 

[jetsticks]

It is a fuel pump. Oil emitted from that or lines means one of several issues. The breather controls crankcase vacuum. If it fails as a check valve, excessive loss of crankcase vacuum happens and flow increases with it able to carry a mist of oil out the line thru the pump and usually on to the air filter cavity as well. Another possible problem is a head gasket failure which then adds compression pressure to the crankcase over powering the breather. Another most common problem is oil over full or diluted by gas. If over full or very thin put a drop of oil on a piece of paper and wait 5 min to see if one consolidated ring is shown or gas creates a secondary ring which indicates gas dilution caused by a carb float problem. some find a flammability test of the oil defining as well. A lighter to the freshly dipped metal dipstick is ok for a badly diluted oil. The fact that oil appears under PTO load is a sign that all of the above are possible. Another quick test requires two people. remove the dip stick and seal the opening with your hand. Have someone start the cold engine and sense a vacuum or pressure. The only value of this test is proof of pressure or lack of vacuum, now you have to find the cause. Also make sure the oil is not hot for this test and not over filled. A compression test is not truly valuable to prove a bad head gasket, in stead a leak down test is needed. Short of that, prove all else not at fault and replace the head gasket. You can buy a manual for the engine. Enjoy.

Interesting ideas that I will try. One question: When doing the pressure test with my hand, should I feel a vacuum trying to suck air or should it be no suction at all?

 

[jetsticks]

Is there a Crankcase Vent that may be plugged? Oil overfilled?

No to both. I had been running the mower since spring after it's initial tune up. I haven't had the problem until now and I haven't added any oil to the engine since this spring.

 

[Affordable in Indy]

I believe I know what your problem is. I've seen this before. What you replaced was the fuel pump, not an oil pump. That is not your problem. The line running from the engine crankcase to the fuel pump should only be supplying air pressure to turn the pump internally. If you have oil in that line and/or oil venting from the fuel pump, the engine crankcase may be getting over pressurized by a blown head gasket. Start the engine, let it run for a minute or two and shut it off. Remove the dipstick and look for white vapor in the oil fill tube. If you see the vapor, that's exhaust fumes leaking into the engine crankcase. You have a blown head gasket.

 

[Tbone0106]

Most Briggs engines in that size range don't even have an oil pump. They have a "splasher paddle wheel" thingmajig instead. In any case, there is no line that goes from an oil pump to the carburetor. What you're looking at is almost certainly a breather hose that vents the discharge from the PCV valve, not to the carburetor, but to the intake.

The most likely problem is that you have overfilled the crankcase with oil. The PCV (positive crankcase ventilation) valve is designed to release pressure and oil vapor from the crankcase; the hose feeds the discharge to the intake and the oil vapor is then sucked in and burned along with the gasoline. On Briggs motors that size, the PCV valve is generally mounted in the front of the engine block, not all that high above the oil reservoir. It may appear to be an oil outlet of some sort, but it isn't. If you overfill the crankcase with oil, the liquid oil can reach the PCV valve -- which it should NEVER do -- and you will have problems very much like you describe.

I've had a number of customers with similar problems that cropped up right after they changed the oil in their own engines. Instead of using the dipstick to gauge the amount of oil in the crankcase, they went by the book and dumped the specified quantity of oil into the engine. Unless you literally turn the mower on its side, you cannot drain all the oil out of one of these Briggs engines. The oil remaining gets added to the specified amount of oil you dumped in..... and you've got too much oil in the crankcase.

 

[johnny7]

Sorry guys. Got bogged down with flooding. Anyway, the B&S model 929133 540cc 21.0 J1940 (?). I tried to send a couple of pictures but I don't know how to make them smaller so they could be sent.

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[bertsmobile1]

What if it’s not coming out of the brass filter but the little slots around the brass filter? Same thing? Blown gasket?

Yes the crankcase is over pressurizing and there are only 2 causes that do not cause a smoke screen when you mow
1) blown head gasket
2) crankcase vent stuck shut .