# 1989 John Deere 1070 spewing fuel from overflow hose



## Wsivik1 (Mar 16, 2018)

Hello there, I have a John Deere 1070 that has been having some issues lately. Last week it was starting to bog down on me, I would have to pump the fuel pedal to bring it back up to operate properly. I figured it was bad fuel so I completely drained the tank, lines, and changed filters. Then I primed the lines and got it started. It ran great for about 6 hours and started bogging down again. Today I start it just fine but when I give it fuel and rpms are higher than idle fuel starts pouring out of the overflow hose located by the oil cap on top of the engine. Video is posted. Any help and input is much appreciated.


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## rhino (Jan 9, 2017)

Ether your fuel lift pump or injector pump is leaking fuel into crank case. Pull dipstick you will find it is over filled and fuel and oil mixture will flow out. Hope that its the lift pump.


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## Wsivik1 (Mar 16, 2018)

rhino said:


> Ether your fuel lift pump or injector pump is leaking fuel into crank case. Pull dipstick you will find it is over filled and fuel and oil mixture will flow out. Hope that its the lift pump.


Will check it out. Thanks for the input will let you know what I find.


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## thepumpguysc (Jan 25, 2015)

WOW.. THATS a lot of fuel.. I would suspect the lift pump has gone out.. POURING fuel into the injection pump, inturn, filling the crank case.
The lift pump is the round gizmo bolted to the side of the injection pump..
You'll need the yanmar #'s off the name plate on the pump..


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## sixbales (May 18, 2011)

Welcome to the tractor forum Wsivik1.

That tube is your crankcase vent tube. Some call it the breather tube. Its purpose is to ventilate combustion gas that gets past the piston rings when the engine is running. Called 'blowby' gas. An engine in good condition will have very little blowby gas venting, whereas a badly worn engine will have a lot of blowby.

You will need to find and repair the source of fuel leaking into the crankcase, and change the engine oil before running the tractor again. Diesel fuel is not a lubricant, and dilutes the engine oil diminishing its lubricating qualities. I too suspect that it is your lift pump causing the problem.


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## willys55 (Oct 13, 2016)

and as sixbales mentioned, if you run it too long like that...say good bye to your bearings


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## thepumpguysc (Jan 25, 2015)

Bearings, cam, crank, rods, pistons.. the works..
You can test the supply pump by> removing it from the inj. pump.
Blow compressed air in the fuel inlet side while blocking the other.. spray the plunger side w/ soapy water..look for bubbles..
Now do the same for the outlet side & look for bubbles.


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## willys55 (Oct 13, 2016)

thepumpguysc said:


> Bearings, cam, crank, rods, pistons.. the works..
> You can test the supply pump by> removing it from the inj. pump.
> Blow compressed air in the fuel inlet side while blocking the other.. spray the plunger side w/ soapy water..look for bubbles..
> Now do the same for the outlet side & look for bubbles.


nice tech tip!


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## big wig (Jul 17, 2021)

does anybody have a repair manual for the 1070. possible a good pdf one i could print. thanks


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