John Deere F935 Diesel Not Starting

1970-1655 · Mar 29, 2009

I have a John Deere F935 with a Yanmar diesel. Last year, it began starting hard. After starting, it would run rough for a minute or so and then run normal. It would smoke cranking and when running rough, then clean out. After setting for the winter, it will not do anything. The glow plug light works, current with test light to all 3. The shut-off solenoid clicks and moves so I feel it is working. Engine turns over fast enough to start. A little light exhaust smoke. Battery is up normal. I checked the air filter, even trying with it off. I gave it a shot of WD-40 in the intake and it sputters a little but no start. Replaced fuel filter and got fuel to bleed at every connection so air is out.

The grass is growing now. I need help. Do I need to have the pump and injectors rebuilt?

Thanks

chevy65 · Mar 30, 2009

first things first
if its been starting hard an rough running id be doing a compression test
was air filter loose when u took it off ????
if so engine may be dusted
If compression is good glow plugs are probably bad
Good Luck Gary

1970-1655 · Mar 30, 2009

Compression checks good. All cylinders within 5 psi. range. Air filter and all connections were tight, just a little dirty. Last year, after it idled for maybe 20-30 seconds, it would smooth out and run strong. This year, it cranls normal with a little smoke. It just does not start.

Thanks for any input ideas.

Dave in Tx · Mar 30, 2009

Open the bleed screw at the injector pump and try to pump fuel with the hand pump. You may be getting air. The fuel line going from the filter to the tank may have a crack in it. Also, i have had several that the plastic line going down in the tank from the fuel guage sender has been cracked or broken. You can take a new hose, hook to the mechanical fuel pump, stick it in the tank, and I'll bet your problem solved If yours has the electric pump, check the lines going from it to the tank. You are surely getting some air in the suction line.

1970-1655 · Apr 2, 2009

I finally found the problems. The fuel filter housing bleed screw has stripped threads. Along with that, the plastic gummy fuel line inside the tank broke off. It is very crumbly so I took the tank off and gave it a good cleaning. Then I saw the slow leak at the bleed screw. Replaced the housing. Now, it starts and runs excellent. It probably had a small air leak in the tank even last year and took until now to fall off.

Thanks to all.

504-2 · Apr 3, 2009

Mt 430 did the same thing last year,new pick up hose and it ran like a new one.

504-2 · Apr 3, 2009

My 430 did the same thing last year,new pick up hose and it ran like a new one.

Mike M · Apr 5, 2009

Still would be a good idea to have the injectors tested and adjust the valves. This is to be done every 500 hrs. on a Yanmar engine.

John Deere F935 Diesel Not Starting

1970-1655

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chevy65

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Dave in Tx

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504-2

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Mike M

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