Oil on the diaphrams of the automatic fuel shut-off

55 50 Ron · Jan 31, 2013

Will the automatic fuel shut-off (620) give trouble if oil gets on the diaphrams?

The oil line from the block had oil in it when I removed the unit from the gas tank. Seems the engine oil shouldn't get all the way up to the shut-off unit if all the pressure line connections are tight and not leaking.

Kent Petersen · Jan 31, 2013

yes oil will get up to the diaphrams it does not make any problems

RLA · Feb 1, 2013

Yes IT WILL create problems.. Replace the
Diaphrams, try to stay away from e85 gas.

Went engine is off the gas will end up draining
into the crank case. Thin out the oil & burn the
bearing & rings out. I Know this for a fact...

You could do away with that style of sediment
bulb & plug off the oil lines.

DONMYEIL · Feb 1, 2013

Engine oil pressure pushes the diaphrams to open the gas valve so of course there is oil in the lines.

55deere70 · Feb 1, 2013

The rebuild kits sold now are supposed to be ethanol safe. Oil pressure is what opens the fuel valve. so I would expect to see oil at the diaphragms. Although I took mine apart to rebuild it and I didn't see any signs of oil even though it was working.

55 50 Ron · Feb 1, 2013

I didn't need the "of course" as I know there is oil in the lines. but I don't believe the oil gets all the way to the automatic cut-off. The air in the line compresses and if the connections are all tight and not leaking, it would sure seem to me that the oil wouldn't get all the way to the cut-off. I would like to know what the compression ratio is in those oil lines as that would determine how far the oil rises. I plan to empty all oil from the lines before re-assembly and use a sealant on the threads to get it as air tight as possible and hopefully keep oil out of those diaphrams. If as some of you say that the oil does cause problems on the diaphrams, then John Deere engineers would not have designed the automatic cut-off so that it would allow oil to get to the diaphrams. All connections need to be air tight to prevent compression leakage or eventually the oil will get to the diaphrams.

Machinery-Man · Feb 1, 2013

When you exam how this works the oil pressure goes in and forces that value open. The heart of this gadget is that little sealing ring on the valve. If this goes bad then all the weight of the gas tank volume is on the float. A miss understanding is that the screw on top shutts of the gas and it does not. Loosening of this just allow a manual release of the valve. Psssssss poor setup if I do say. By the time this shut off works you would have already ruined and engine as it would probably run 2-3 minutes before without pressure. Why John Deere ever invented this I don"t have a clue. The old manual shut off is light years ahead.

RLA · Feb 1, 2013

Ron the line Y's, the oil pass's through it, so
if your gasoline turns black all air would be
gone. & the gasoline weight with engine off
will force itself back there the small oil line
& carb float. It WILL fill the crank case with
gas until the tank is empty. It will surprise
as quick it happens, once the diaphrams fail.

55 50 Ron · Feb 1, 2013

I understand how this works and I agree completely with what you say. If there was to be a engine shutoff from an oil pressure failure it should have shut down the ignition.

55 50 Ron · Feb 1, 2013

Yes, thanks for your response and I agree with you. I see that Steiners (and maybe other suppliers) are selling the old style (non shut- off) with the note that many owners of 2 cyl tractors with the automatic "feature" are converting back to the manual shut-off.

Loosehandle · Feb 1, 2013

Get rid of it!

SMinWi · Feb 2, 2013

(quoted from post at 21:33:47 02/01/13) When you exam how this works the oil pressure goes in and forces that value open. The heart of this gadget is that little sealing ring on the valve. If this goes bad then all the weight of the gas tank volume is on the float. A miss understanding is that the screw on top shutts of the gas and it does not. Loosening of this just allow a manual release of the valve. Psssssss poor setup if I do say. By the time this shut off works you would have already ruined and engine as it would probably run 2-3 minutes before without pressure. Why John Deere ever invented this I don"t have a clue. The old manual shut off is light years ahead.

No it's not a poor setup if it's working right. It was made by AC not John Deere

Oil on the diaphrams of the automatic fuel shut-off

55 50 Ron

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Kent Petersen

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RLA

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DONMYEIL

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55deere70

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55 50 Ron

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Machinery-Man

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RLA

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55 50 Ron

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55 50 Ron

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Loosehandle

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SMinWi

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