Hitachi 120-2 Fuel Problems

ShaneeOC · Mar 29, 2020

Hi Everyone,

I have air in the fuel system. My machine will start but it cuts out. I loosened the injectors, and there's bubbles of air coming out. I cleaned out the fuel filter and refilled it. Any suggestions what to do next??

Ronsii · Mar 29, 2020

Find where the air is getting into the system...... since you just cleaned the fuel filter.... why did you do this? and how about some more details???

ShaneeOC · Mar 29, 2020

Cheers for the reply. My son ran machine low on fuel and it stopped. Sorry, it was actually the water separator we cleaned.. So, the machine fires up, and runs for a small period of time. Then it cuts out, i'm wondering is there a blockage where the pipe exits the tank.

Ronsii · Mar 29, 2020

Low on fuel will stir up all kinds of crud in the tank.... this will lead to blockages in the tank at the feed tub/ plastic strainers in the banjo nuts on certain fittings... and IF you didn't replace the orings/seals in the strainer when you took it apart if could be sucking air there as well as other places.... didi you use the primer pump to restart??? how bout' some details on the machine???? year, hours, motor, serial, etc...?????

Have you looked in the fuel tank to see how much rust/debris is in there... if the machine is old enough then there probably is plenty... if you haven't replaced the fuel filter it probably needs it.

Bls repair · Mar 29, 2020

Did fill filters with fuel before starting ?

Ronsii · Mar 29, 2020

Did you take the banjo fitting off the 'input' side of the fuel water strainer? there will probably be a plastic strainer in it... depending on year.... this WILL be clogged up!!! clean it carefully and do not overtighten it when replacing it.

Delmer · Mar 29, 2020

You probably have two problems, a clog of debris somewhere, and a suction leak somewhere else. I'd take apart everything between the lift pump back to the fuel tank, including the pickup screen in the tank if at all possible. Replace any suspect rubber hose. The plastic bowl water separator (if you have that Japanese style) is terrible for leaking air, but fix the seal, don't remove it, unless you want all the trash to go to the poor neglected banjo bolt screen, even worse.

Ronsii · Mar 29, 2020

Also depending on what kind of service life the machine has had the banjo seals could be leaking... these are a common part and should be replaced if they look suspect at all, you need two seals per banjo fitting.

thepumpguysc · Mar 30, 2020

Ronsil is correct.. the BANJO BOLTS have screens in them, well at least some of them do..
I KNOW the 1 BELOW the hand primer does, or its supposed to..
Its on the fuel inlet line below the HP.. on the supply pump.
Thats IF u have the "in-line" inj. pump..
DONT just clean out a filter.. REPLACE it..
Good Luck.

ShaneeOC · Mar 30, 2020

Hi men, thank you for your replies. The year of the machine is a 1990, and has 23000 hours done. Today, I blew air back from the water separator threw the line into the tank and it seems free. Now, I'm priming the fuel line with the fuel pump and there is diesel flowing out the bleed screw on the top of the fuel filter. But, it has little bits of air coming with it.

Delmer · Mar 30, 2020

What if you go back to it after an hour and prime again, do you get a bigger bubble of air, and then continuing little bits of air?

Sounds like what everybody is saying. Did you remove the banjo bolt in the transfer pump inlet? triple check the water separator? (do you have a plastic bowl style separator? could even smear outside the seal area with grease to see if that stops the air bubbles), triple check any rubber hose? especially near the ends where they bend.

ShaneeOC · Apr 1, 2020

Hi guys,

thank you for your help.

The machine is running. It could have been one or two things. 1). Banjo bolt at bottom of lift pump was removed, the copper washers were heated and put back on. 2). The fuel water separator drain off cork was taken off, the cylinder was cleaned and the cork was put back on with plumbing tape, and it was tightened. All the components were put back on, machine was primed and it started straight away.

joeblow · Apr 1, 2020

Also crack the fuel tank drain and see how much crap/water you get out it.That should be done at least once a week.

Ronsii · Apr 1, 2020

Glad to hear you got it running again

I don't remember ever seeing one of hitachi's of that vintage using copper washers like a brake system.... Stock components are the rubber bonded sealing washers which seal perfect even when being reused.

thepumpguysc · Apr 3, 2020

GOOD DEAL.. Happy Tractoring..

Jakex120 · Apr 13, 2020

If you don't have a replacement metal/rubber seal handy but do have an o-ring selection just pull that old rubber off that washer and find an o-ring to take its place..it will usually hold its place inside washer as you retighten...

Hitachi 120-2 Fuel Problems

ShaneeOC

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Ronsii

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ShaneeOC

New Member

Ronsii

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Bls repair

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Ronsii

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Delmer

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Ronsii

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thepumpguysc

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ShaneeOC

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Delmer

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ShaneeOC

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joeblow

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Ronsii

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thepumpguysc

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Jakex120

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