JD B

[Steve Fawks]

I have a 1951 B which gave me an oil bath through the exhaust pipe while brush hogging one day. Figured I'd busted a ring or worse. Took it to a 'tractor guy'. He said it had 100 compression on both cylinders and couldn't justify tearing it apart.

Took it home, drove it around a little, then hooked the mower on the back, and it didn't take long to start blowing a little smoke. I shut off the mower and parked it. Later, I started it and drove it a little around the farm where it would throw a little piece of 'soot' out on the hood once in a while.

Since I'm not a genius at this, any clues?

Thanks,
Steve

 

[RandyB(MI)]

Check to make sure your air stack isn't plugged up with mud dauber nests or worse. That would cause the engine to suck oil out of the oil bath reservoir. Could also be plugged up drain back holes in cylinder head causing oil to fill up valve cover and be sucked through valve guides. Lastly, crankcase ventilation system and/or plumbing could be plugged or not operating correctly causing a lot of pressure in crankcase.

 

[Resting Relics 1]

Steve,
I assumed you checked your oil level. Just check to make sure it didn't get gas past the carb and the crankcase is severely overfull. Common problem. Could also be a ventalater pump problem. Good Luck! John

 

[toot]

Sounds like the ventilator pump in the fanshaft.. The ventilator is supposed to receive oil from the oil pump and blow that oil along with fresh air from the air cleaner out the rear of the pump housing into the governor. This oil is the primary source for lubrication to the bevel gears and rear fan shaft bearing. The crank case fumes are what is supposed to go OUT the tube between the valve cover & the carb's inlet pipe because they're pushed that way from the fresh air being pushed IN by the pump.

There is a hole in the gasket stack between the governor housing and the pump housing through which this air and oil are supposed to both flow I believe. If that hole is plugged or closed off by sealer or a gasket that got out of place then the oil would have to go through the gaps betwen the pump rotor and housing then through the rear fan shaft bearing. At higher rpm the oil may not be able to run back by gravity as fast as it is delivered especially if the ventilator pump is not working correctly or well. The oil can back up in the inlet tube eventually being pumped INTO the air pipe just outside of the air cleaner as it is headed to the engine.

There were two styles used on the last series of B's. The last series of B's (I believe, square axle - 1950 and up) used a long tube about 5/8" in diameter that lay along side the fan shaft between the air cleaner and the ventilator pump. The other style (the earlier late models with round axles and straight six speed 1947-1949) used the fan shaft tube and a short inlet tube between the air cleaner & the front fan shaft bearing housing. If yours has the long tube along the fan shaft try removing it from the air cleaner and then run it in the same manner as you do that makes him smoke. It should only take air in through this tube. The line should not have any oil come out of it. If yours does not have this tube along the fan shaft there should be a fresh air tube from the air cleaner to the front fan shaft bearing housing. Removing that tube should tell the same story in the same way if the vent pump is the problem. You should not find fumes or oil coming out of these tubes in either design. They should be the fresh air intake tubes

If with these tubes disconnected you eventually have oil run out of them.. time to rebuild it.

 

[Anonymous-0]

I believe that's a rather nice explanation!

My compliments.

 

[Steve Fawks]

You guys are great. This should get me on the right track!
Thanks