57 JD blowing oil out of intake stack

ronjr · Jun 25, 2012

I have a 1957 John Deere 720 that is a gasoline model...I am not experienced with tractor repair and could use some help...

The tractor starts and runs but is very tired and seems very low on power...starting the pto running with mower attached really works it...

The tractor sputters or backfires through the air intake stack every little bit and blows oil out...I assume it is the oil out of oil bath air cleaner...

Anyone got any Ideas where to start on this issue?

old · Jun 25, 2012

Has it sat a long time at any point in its life??? If it has it could be sticking rings and sticking valves. Pull the plugs out and fill the cylinders with ATF and also pour as much as you can down the exhaust pipe and let it sit a few days. Be sure to put the plugs back in so as to keep dirt etc out and put them back in before filling the exhaust. Then after a few days pull the plugs out. May want a pan under so catch the atf and spin it over with the plugs out. Start it up and see if that helps

ronjr · Jun 25, 2012

Yes it sat for 2yrs until now...it was tired when we parked it and #2 is wet with oil...

ronjr · Jun 25, 2012

Just to make sure I understand...after sitting for a few days full of ATF fluid will it all drain out when I pull the plugs? or should I crank it with them out to work it out?

thanks

wilamayb · Jun 25, 2012

Sounds like it could be a lean running situation. Is the exhaust manifold getting super duper hot?

Do you have good fuel flow? It is possible that the oil pressure shutoff under the tank is not releasing enough fuel flow. Do you have good oil pressure? Any inline filters in the system? Loosen the drain on the bottom of the fuel bowl and hold down the knurled nut on the oil pressure controlled fuel shutoff. Does it run a full stream for 45 seconds? If not look for your obstruction.

How is the condition of the ignition? Point contacts clean and free of corrosion? Tractor producing a blue spark through both plugs while cranking? If not look for the reason for weak spark.

If you do suspect a sticky valve run a compression test on both cylinders to see if they are similar in value.

old · Jun 25, 2012

Some but not all will drain out with the plugs out so you need to turn it over to get the rest out. If you can do so by hand it is better since then it will not shoot 10 feet and make a big mess

fixerupper · Jun 25, 2012

The sputtering and backfiring through the intake doesn't sound valve related to me on a two banger. Could very well be ignition. Maybe bad plugs or points. Seems like when the condenser shorts out it cuts out for a few revs and then fires, igniting gas fumes in the muffler making a loud backfire, but usually a condenser doesn't cause popping up through the intake.

The oval muffler on my 630 looks pregnant from a couple of episodes of shorting condenser. Jim

BushogPapa · Jun 25, 2012

Sounds very much like a re-build would be the best move..
FRESH Valves and new rings on well-honed cylinders would improve things a great deal..

If it would need a New Bore..that is even better..
Complete kits are readily available..

You won't believe what power that Moose will have, if Fresh..!!!
Well worth the time..they only need it about once every 50 Years..!!!

Ron..

buickanddeere · Jun 25, 2012

Adjust the valves. Replace the points &
condensor.Replace the ignition wires with solid core
and use Autolite 3116 plugs. Clean the fuel filter
in the carb and in the sediment bowl. Adjust the
idle screws as per the operator's manual.

Anonymous-0 · Jun 26, 2012

I would do a wet and dry compression test,before you do anything.

57 JD blowing oil out of intake stack

ronjr

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old

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