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EA81 Hitachi Carb rejetting


Guest brattysvx
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Guest brattysvx

How much would I be looking at spending to get my carb rejetted. My 86 Brat is running real rich (seems to be getting richer by the day) Mpg is around 20-21. Any good place to take it around central PA?

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Guest beauregaardhooligan

I'm with the Skipper, clean the carb. Run your favorite cleaner thru it for at least a couple of tanks and *change those fuel filters!* If it gets too cruddy, go for a rebuild before messing with the jets. They worked good before, right?

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Guest brattysvx

Well I just had an inspection and everything else seemed fine when he checked it the plugs are almost shot though after about 4k. The float is just above the circle now (I had it just below but it ran out of gas around 3500rpm). Not good on the hills. I rebuilt the carb when I got it and haven't gotten over 230 miles per tank or 22mpg.

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you say you rebuilt it.

Do you by chance remember changing the "power valve"???

 

I have seen these work loose (and go bad). Since they are located below the fuel level in the bowl, if they are loose and or "leaking by". The engine will run rich, and as you said, get progressively worse.

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Guest brattysvx

tight as can be. Just lowered the float down to right in the middle of the circle. We'll see if that does anything but it ran rich even when it was below the circle (last set of plugs showed the tell tale signs.

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did you replace the power valve?

Some kits have one some don't,

this could still be the problem if it is leaking

or "passing gas" when it shouldn't

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Guest beauregaardhooligan

If the float level is too low it will lose power in a turn, a very sensitive adjustment.

Did you replace the float valve seat and needle? There is also a filter screen in front of the float valve, be sure it's clean. Blast out any little hole/passage you can find. :cool: Wear glasses!

What about the fuel filter(s)?

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Guest brattysvx

Yeah, it was a new float and needle, screen is okay and the fuel filters have been replaced twice w/o a change. I'd be happy with everything if I could just get up to around 25mpg

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Guest brattysvx

So I decided to rebuilt my "parts" carb that I got from the junkyard. Spent a good 15 hours cleaning it and getting it together. Slapped it on my brat and it jumped to life. This one doesn't want to run unless the vacumn hose for the choke (those two dashpots (I think) behind the pass side of the car) is disconnected. Without it on it'll idle and run still on the rich side but after driving for a while it'll tend to stall when you come up to a light. Float's right dead center in the middle of the spot. Any thoughts out there??

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Guest beauregaardhooligan

Make sure the choke is fully open when at operating temp. Lean out the fuel-to-air a half turn at a time. Don't get too lean or it can run hot.

If you lose power in a hard right you need to raise the float level.

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Guest rubuild

If it runs better with the choke closed or part closed you have

a massive vacuum leak or plugged idle circuit, sounds like your other carb is in better shape, reset float levell and check vacuum routing. Check that the bowl vent valve ( black round valve that clips into back of air cleaner) is connected to the very top port of carb, above fuel line fittings & not the secondary air control port on the back side. If fuel is spitting from the primary venturi at idle, you have a plugged idle circuit, and it's sucking fuel from the main circuit.

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Guest brattysvx

checked everything on that bad boy. Even switched all the internals from the rich running one and it wouldn't work a bit. Just simply rebuilt the rich one and put it back it. Still seems rich but oh well no emissions testing til next year in PA. If I upgraded my coil to the accel would the plugs burn more fuel when they fired??

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Guest Subi81

Bratty I just had a simalar problem on my 81 wagon Hitachi. It was running so rich it wouldn't pass smog. It turned out that the primary slow jet had worked its way loose and was just floating in it's seat. The slow jets on my hitachi are the ones that are under the little plugs really deep down in a hole, they can be accessed by taking off the carb top and unscrewing the little plugs. Hope this helps

 

Good luck

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