4320 losing power

MaverickM23 · Jun 16, 2016

Just got done mowing with my 4320 on some big hills. At first everything ran great towards the end it started losing power and acted starved for fuel when I was going out along up the hill. When I turned back and was headed down along the hill it seemed to run better. I was going to change the fuel filter but the parts store is closed I will get one tomorrow, but does this seem like my injection pump is going out. Occasionally it would do this before like sort of speed up at times. The previous owner said that the fuel was turned up to it but looking at the pump it is still wired with the little round thing to let you know if anyone was in it. The tractor has 6100 hours and the tach works. The fuel was getting low but wasn't that close to being empty. It blows some black smoke when running hard but then at idle it smokes a little bluish white. Any ideas, sorry for all the questions but this site is the best for answers.

Dieseltech · Jun 16, 2016

If the fuel supply, and filters are OK the injection pump may need serviced. When the retainer ring breaks apart the bits start plugging the return side, causing loss of power, and shutting down in severe cases. Just repaired a 4020 pump for the same trouble..

coonie minnie · Jun 16, 2016

Start with the filter and a good stream from the tank. Poor fuel flow is a common culprit.

Tx Jim · Jun 16, 2016

Ditto what coonie minnie stated.

MaverickM23 · Jun 16, 2016

Alright I will start with a new fuel filter in the morning and let you know what I find. The other thing it is doing is making a almost screeching noise under the dash when I raise the mower and turn the wheel what should I look at for that it goes away when driving straight and the mower is down and its wide open. The hydraulics don't hold the mower up it slowly lowers not sure if that is part of it or not.

chuck from neb · Jun 16, 2016

Bottom of the fuel tank could have trash plugging it too

MaverickM23 · Jun 17, 2016

Well you guys were spot on drained the sump and changed the filter and it runs like a champ. I tried posting a picture of the filter I tore it apart and it was bad thanks for the help. Now just have to figure out this hydraulic noise under the cowl

Tx Jim · Jun 17, 2016

(quoted from post at 13:51:55 06/17/16) Well you guys were spot on drained the sump and changed the filter and it runs like a champ. Now just have to figure out this hydraulic noise under the cowl

Thanks for update, Hyd screeching noise could be pressure control(priority) valve trying to close from low stand-by pressure. I'd suggest to check stand-by pressure. It should be 2250 psi. Mower lowering could be caused by leaking rockshaft control valves or leaking RS piston seal

David G · Jun 17, 2016

Pumps can be turned up and still sealed, the pump shop will do that.

MaverickM23 · Jun 17, 2016

Alright how do I check that. I haven't worked a lot
on hydraulics. I'm guessing I need to plumb a
gauge in but not sure where to do that

Tx Jim · Jun 18, 2016

You can attach male quick coupler tip to 5000# gauge and plug into rear hyd breakaways. Activate lever the correct direction to read stand-by pressure which should be 2250 psi.

MaverickM23 · Jun 20, 2016

Alright I will check that and post back a new post
with what I find. Thanks

4320 losing power

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coonie minnie

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Tx Jim

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