Hitachi zx120 fuel issue

rbcanaday · May 6, 2019

i think I’m having a fuel issue with my hitachi zx120.
When I first bought it a year ago I had to pull the tank and pressure wash it out. It’s been good for a year now but I don’t run much.
Now it’s started skipping and all but shutting down. I changed the fuel filter and it was nasty.
It ran good for 15 mins then back to skipping/sputtering. I changed filer again and drained tank low as I could. Bottom of tank looked fairly clean. It ran good for 15 mins or so then stared acting up again.
Does any one have experience with the ZX fuel system. I’ve read the EX machines had screens in banjo fittings but I haven’t checked that yet.

I was planning to pull the line from tank and bow it out. It’s therw a certain way to bleed the air from the line or will the system bleed it’s self.
Sorry for long post, I’m frustrated. Any help would be a appreciated!

excavator · May 6, 2019

The fuel pump inlet banjo fitting should have a screen in it.

92U 3406 · May 7, 2019

If its got that electric fuel transfer pump on it, check the screen inside. Have seen those clog up bad.

rbcanaday · May 7, 2019

Does it have an electric fuel pump? I haven’t traced the line out yet, so I haven’t located the pump.

What’s the procedure for proper bleeding once I get air in lines? Is there a primer pump? Or do I have to crack injectors? Or?
My tractor has a small primer pump that helps bleed all the air out.

Delmer · May 7, 2019

If it starts and runs it will bleed the air on it's own. If you still have air in the system, then look for a cracked rubber line on the suction side.

"It ran good for 15 mins or so then stared acting up again" this sounds like a suction air leak to me...

Look at your injection pump (if you have one? this is typical of Japanese inline pumps not specific to anything) and down low hanging off the side will be a piece with a round knurled knob on top, that's the priming pump if you run out of fuel, or change filters, that knurled knob unscrews and pops up and you pump that. On the underside of that pump, pointing toward the ground, is a banjo bolt that has a screen inside of the bolt, take the bolt out, unscrew the screen, clean and replace, careful not to lose the washers. If none of this paragraph makes sense after looking at your machine, ignore.

rbcanaday · May 7, 2019

Delmer- that made sense to me.
Per you instructions I have found the primer pump and see the banjo fitting your taking about.

Now I see some issues with getting to the banjo fitting. It’s a good ways down the side of the motor and the motor is squeezed in there. I may be able to pull a panel underneath and get the the banjo fitting from the bottom. If not I’m not sure how a man could get a wrench on that banjo bolt. Guess nothing is easy.
If someone has done this please elaborate if they went from bottom or if that’s not an option.

THANKS Delmer

excavator · May 7, 2019

You can probably go from the bottom but I usually go from the top, keeps from having fuel running down into your arm pits. It's a bit of a stretch and alot of braille but that's what working on this stuff is about.

thepumpguysc · May 7, 2019

U may have to take off the other line but I think u can get it w/ a socket & ratchet..
OR a "stubby" 19mm-3/4 wrench.

rbcanaday · May 7, 2019

Excavator I can reach it just ain’t sure about all that Braille haha.
I may just try the bottom and shower afterwards.
I sure hope I can find the problem. Runs ok for 15 then spits and sputters like no fuel.

rbcanaday · May 7, 2019

That’s helpful thepumpguysc. I was already wondering what size it was.

Delmer · May 7, 2019

Let me ask you this, if you're dreading getting that bolt out, do you have a water separator between the fuel tank and the primer pump? And have you serviced it? The reason I ask is that system was designed to have a water separator (or it should have been!) and if the separator has not been bypassed, then there's much less chance of junk plugging that banjo bolt screen. Usually the water separator is bypassed, leaking air on the suction side perhaps? I'd replace or closely inspect any rubber hose between the tank and the primer pump before going at that bolt from underneath.

rbcanaday · May 8, 2019

Delmar- the water separator is still there. It’s right beside the hydraulic tank. I’ve took it off and cleaned it out but it’s basically just a sediment bowl. There is nothing inside it. I was thinking there should be atkeast a screen in it but whatever is supposed to be inside was missing when I got it.

92U 3406 · May 8, 2019

rbcanaday said:
Does it have an electric fuel pump? I haven’t traced the line out yet, so I haven’t located the pump.

What’s the procedure for proper bleeding once I get air in lines? Is there a primer pump? Or do I have to crack injectors? Or?
My tractor has a small primer pump that helps bleed all the air out.

Its been about 6 years since I worked for the Hitachi dealer but I did have a similar issue with a machine. Want to say it was a ZX200-3 but my memory isn't the greatest. It would idle fine. Rev it up, put it to work and after about 10-15 minutes it would stumble, lose power/RPM and smoke white/blue. Pulled the fuel line off that electric transfer pump and had very little fuel flow. That's where I found that little screen inside the pump and it was about 80-85% plugged. Cleaned it out and that machine ran great afterwards.

I think a lot of the small to mid size ZX, ZX-3 and possibly ZX-5 used the same style of transfer pump. Like I said its been a while since I hung out in the pumpkin patch lol.

rbcanaday · May 8, 2019

92U 3406- I don’t see a electric fuel pump in this machine. I traced all the fuel line yesterday.
Leave tank to the water separator. Then to priming pump and filter.

It’s confusing because I see a lot of the ZX machines have the electric pump and also have more filters by the hydraulic tank.

My machine seems to be set up more like the EX machines.
It’s has all the ZX decals and I was told it was a 2004 but I have no way to verity. The local dealer says they can’t use the serial bc it’s a Grey machine.

excavator · May 8, 2019

Time to get in there and pull the screen out of the banjo bolt before you get 5 other ideas.

John Shipp · May 9, 2019

Here's one of those 5 more! I pulled about 12m or more new rubber hose through a machine like that once, actually might have a few more metres coz I remember heading back to shop for one more length. First section from dirty tank was completely bunged up with crud, and a pinprick hole in the final section of hose going to lift pump. Saying you cleaned tank out reminded me

rbcanaday · May 9, 2019

I will pull the banjo fitting this weekend and update everyone after.

thepumpguysc · May 10, 2019

Lemme know if u run into problems.. I'm only an hr away.. {Santee area}
I do the 8 mile canoe trip atleast a couple times a year.. FUN, FUN FUN..

rbcanaday · May 13, 2019

I pulled the banjo fittings. The one at pump wasn’t too nasty. So I stared back tracking. There was another strainer in banjo fitting at water separator. It was NASTY. I got them cleaned up and that seems to have fixed the fuel problems.

THANKS EVERYONE.

rbcanaday · May 13, 2019

Now after we got if fixed someone busted the front windshield and bottom glass. Dang it.
The stump bent the window frame a little but I’m pretty sure I cm straighten that out.
Where are the best places for new glass? Anyone know of a place I might be able to find some used glass??

thepumpguysc- it’s good to know your close by. I’m not far at all.
What all do you work on?

Hitachi zx120 fuel issue

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