My M120 loses fuel prime when fuel tank level drops below 3/4 .Also when working in field when right side is up hill it loses power .Have checked fuel lines and water separator to make sure they don’t leak . Any ideas ?
M120 fuel
- Thread starter Tcbloom
- Start date
On many tractors, the fuel pump is more properly named a lift pump as it takes fuel when the tank level is low and lifts it up to the injector pump.
On a full tank gravity alone can deliver the fuel.
A sign of a failed lift pump is the engine not running as the fuel level drops to the point where gravity cannot deliver it to the injection pump.
On level ground the no delivery level by gravity will be higher than if the tractor is climbing a hill where gravity cannot deliver.
On a side slope same situation.
Check your lift pump as I expect you will find it is not working.
Does the hand priming pump work properly?
Dave
On a full tank gravity alone can deliver the fuel.
A sign of a failed lift pump is the engine not running as the fuel level drops to the point where gravity cannot deliver it to the injection pump.
On level ground the no delivery level by gravity will be higher than if the tractor is climbing a hill where gravity cannot deliver.
On a side slope same situation.
Check your lift pump as I expect you will find it is not working.
Does the hand priming pump work properly?
Dave
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RCW
Well-known member
Lifetime Member
Equipment
BX2360, FEL, MMM, BX2750D snowblower. 1953 Minneapolis Moline ZAU
I would definitely suggest you get a workshop manual (WSM).
Also, as Dave references, the parts diagrams from the Kubota website are handy.
Agree to the legal stuff, then put in your M120 model number:
apps.kubotausa.com
Also, as Dave references, the parts diagrams from the Kubota website are handy.
Agree to the legal stuff, then put in your M120 model number:
Kubota Tractor Corporation - Illustrated Parts List
- K-PAD - Parts Lists - Illustrated Parts Lists - diagrams
I am wondering if part of the hand primer assembly is also the lift pump I mentioned earlier.
I cannot find a WSM to confirm and the parts illustrations do not name it.
Dave
dvcochran
Active member
Equipment
Kubota M9000, New Holland TN90, Deere 2640, Vermeer 504N, Vermeer 504SI, more
I chased a very similar problem back in the summer. The tractor would run fine for a while then smother down and almost die.
I even dropped the tanks to check them out. After researching the problem I replaced the lines from the tank forward at each point (filters, lift pump, injection pump) and it fixed the problem. I have seen in several posts on different M models that this is a pretty common thing.
I never saw any kind of fuel leak but had to be sucking air from one or more connections.
I even dropped the tanks to check them out. After researching the problem I replaced the lines from the tank forward at each point (filters, lift pump, injection pump) and it fixed the problem. I have seen in several posts on different M models that this is a pretty common thing.
I never saw any kind of fuel leak but had to be sucking air from one or more connections.
Dave... All the M's have saddle tanks and they are all BELOW the injection pump so the lift pump has to pull the fuel from the tanks, through the fuel filter and water separator and deliver it to the injection pump. It's not gravity fed.
One thing I would do is pull the pickup tube from the tank (I believe it will be the right side tank (same one the ending unit is in) and check the pickup tube length and make sure it's pulling from the bottom of the tank, then I'd replace the fuel lines from the tank to the spin on fuel filter and separator and then the hoses to the lift pump. From there on the fuel is under pressure do a leaking hose would spray diesel all over the place. Suction side, you'd never see a hole in a hose, you'd just suck air.
One thing I would do is pull the pickup tube from the tank (I believe it will be the right side tank (same one the ending unit is in) and check the pickup tube length and make sure it's pulling from the bottom of the tank, then I'd replace the fuel lines from the tank to the spin on fuel filter and separator and then the hoses to the lift pump. From there on the fuel is under pressure do a leaking hose would spray diesel all over the place. Suction side, you'd never see a hole in a hose, you'd just suck air.
Not all of them, Flip. My M4700 has it’s fuel tank above the engine, just forward of the instrument panel just like an old Ford.
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I agree my '11 M7040 has only one fuel tank on LH side under cab. My neighbors M7040 engine continually stopped & he replaced some cracked fuel lines to solve the problem
Jim and George....
My M9's have a mechanical lift pump on the side of the block. Far as I know, the pump on top of the fuel filter only creates a vacuum in the filter to draw fuel into it,
I probably should have refined my comment to refer to the larger ones.
My M9's have a mechanical lift pump on the side of the block. Far as I know, the pump on top of the fuel filter only creates a vacuum in the filter to draw fuel into it,
Dave, I'm having the same problem. My manual pump doesn't seem to work except occasionally. Sometimes I see bubbles coming out of it when I've used it after changing the separator O rings as I thought this was the problem. You think it's my hand pump, even though it's screwed shut?
Did you ever figure out your issue? I'm having the same one. Engine drops to 100-200 rpm and either dies or comes back. Has done it turning on flat ground, discing down hill, discing up hill.