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My grandson was mowing lawn and he came in and said the mower quit. I went out and look at it and the deck wis covered in oil and the dipstick just barely has any on it. I filled it with oil and it cranks over, but the oil just runs out the bottom. Thinking it possibly is the cranks seal, but haven’t checked yet.

A JD 140 rider had different engines on them.

We need the engine numbers off the valve cover if B&S or the white label if it is a Kohler.

Not very many of these had an oil shut off circuit

It’s a Briggs & Stratton. I pulled the mower deck off and the crack seal was laying on top of the drive pulley in one piece. What could cause it to come out? My thought is crankcase pressure.

Little history on the engine. I had to overhaul it at 110 hours the rings were shot. One piston had no compression the other had 20 pounds. I now have 250 hours on it.

This whole problem is pointing at overheating due to excess debris in the cooling fins and or a bad crankcase breather from the very beginning. It should not have had issues at 110 hours unless the oil was never changed like it is supposed to be.

This whole thing is pointing at overheating due to excess debris in the cooling fins or a bad crankcase breather from the very beginning. It should not have had issues at 110 hours unless the oil was never changed like it is supposed to be.

Were the cooling fin heat shields left off when you did the overhaul? They must be in place to get force air from the flywheel colling fins. Often times people do not realize why they have to be in place.

Auto Doc's said:

This whole problem is pointing at overheating due to excess debris in the cooling fins and or a bad crankcase breather from the very beginning. It should not have had issues at 110 hours unless the oil was never changed like it is supposed to be.

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I clean the cooling fins every time I use it. I got it from my brother in law when it us 18 hours on it I change the oil every 25 hour. Air filter is cleaned once a month and I replace it every 50 hours.

Bob

Good, sounds like you have been diligent in your efforts to maintain this.

That leaves the breather as a suspect or piston and ring wear issues. There is no accurate way to test the breather that I have found so I recommend it be replaced if you are sure the rest of the engine is in sound condition.

What are your current compression readings before going any further? I hate to condemn any parts or an engine without thorough testing.

Try pulling the valve covers and then use the compression hose (with Shrader valve removed) attach shop air with both valves fully closed on a cylinder being tested.

See if a lot of air escapes through the dipstick tube or just a little. There should only be very little air escape.

If there is a lot of air escaping, the rings and piston are not sealing to the cylinder properly. Bad news.... It will need an engine.

I’ll check compression tomorrow if I get a chance. I’ll also do a leak down test if I can find my setup.

I start working harvest late this week, so I have to either get this one fixed or buy a new mower. Won’t have any time for the next 6-8 weeks.

Thanks for the help.

I put the old seal back in (temporarily)in and filled with oil. Did a compression test both cylinders test at 140 pounds. There is some air coming out of the intake when I pressurized the cylinders, both sides. I got it started and it run as smooth as it always did.

Is there a vent crankcase vent the hose that runs into the intake just below the air cleaner?

Bob

Part #8 of this parts list is an example but match your exact engine numbers.