Hitatchi Carb Problems

[JAS]

This is for the carb guru's:

The carb on my daughters 79 210 loosened up at the plate above where it atatches to the manifold. Got that tightened up, and the carb is dumping fuel like crazy down the primary. The float is set correct, and no vacuum leaks... bogs down the engine in 5 seconds from flooding, runs fine above 2,500 rpm to keep it from flooding... I did check the float and adjust lower, checked accelorator pump, blew out the tank where the float is and all ports with the top off... Still the same, the idle rich screw adjustment, i set to all the way in at this time... no help. Help?

[LenRobertson]

Take a look at this thread:

 

http://community.rat...340-carburetor/

 

Toward the end, I describe what worked for me - taking out the idle mixture screw, spraying carb cleaner in the hole and blowing out the hole with compressed air. It seemed to solve the problem, at least for now.

 

Len

[JAS]

Did all that, still sucking fuel like a pig out of the primary venturi at idle untill about 2,000 rpms, then seems to clear it? or fuel to air finally works... will only run for 5 seconds at idle before you have to up the rpm to clear it out again, or down again for flooded.

[datzenmike]

Look at the front of the carb. There is a glass front or a small round sight glass with a dot on it. At idle were is the fuel level???

[JAS]

Midpoint on the fuel level glass... went to normal for a minute on the second try of cleaner down idle rich screw port, then down the throat, put screw back in, 1 1/4 turns open, started,... flooded, but nursed to run, then idle.. got to put cleaner down throat while running, then cleared up after i adjusted the linkage idle screw, then ran great for a few minutes, then back to flooding... (odd, at normal run, its a litle high on RPM for normal, adjusted it back to about 800 rpm, then the problem came back some... just messing with the linkage a little...)

[datzenmike]

Has the carb been taken apart? Any chance the air bleeds or jets could have been mixed up.

[LenRobertson]

Since you have gotten it to idle normally some of the time, I keep thinking it is piece or pieces of gunk blocking the idle circuit. Blowing through the idle mixture screw hole after removing the screw may be just blowing it back into the float bowl. You might try taking the side cover off the float bowl and clean the inside of the bowl as well as possible. But there is the danger of damaging the cover gasket so you create a leak. I have sprayed carb cleaner down into the float bowl through the bowl vent tubes ( those tubes that stick up in to the carb throat at an angle, and let it soak for a bit. Then start the engine and the cleaner will burn on through the engine with the gas. Possibly this would suck carb cleaner through the idle circuit and soften the gunk so it sucks on into the engine. I've actually wondered about trying to pressurize the float bowl with LOW pressure compressed air through one of the vent tubes with the other vent plugged off. I don't know if it would blow through the idle circuit or not. Might end up with gar/air mixture blowing out everywhere.

 

Len

[JAS]

I have taken it down to the float bowl to clean it out and reset the float level, cleaned and blow dry bowl, re-assmbled, still what it was... then took out the idle screw and cblew cleaner through it. and down the venturis and throat. Blew i all out with compressed air again, started... still the issue, got it to idle rough, blew cleaner down the throat and venturies again, adjusted idle on linkage to get more rpms, started working good. then it was about 1,100 rpms, started to lower rpm on the linkage, went back to bad again....

 

I have not removed any jets, venturies, nothing except the top to check accelorator pump (good) and readjust the float, mid level now and steady.. was a little high when i started...

 

This is my daughters daily driver, for myself long term, i would do and have done a weber install to fix this in the past, but daughter is part of the working poor.. and poor old dad has 4 adult kids with their hands out too.... So its fix the Hitatchi carb....

 

Thanks,

[ggzilla]

Blocked idle circuit will cause less fuel, so its not that. Blocked air jet will cause too much fuel.

[JAS]

Begining to wonder, tailpipe stinks of gas, the gas tank has visibly gone down since this started. Wondering about wires around the carb linkage... Was messing I that area with the idle when it came to life, then started messing up again after I played idle linkage area.

[LenRobertson]

I'm thinking you may be to the point you'll have to take the carb top off and remove the idle air bleed or some of that stuff I've never done myself, and keep blowing air through everything. I found this page of pics on the Datsun1200 site: http://datsun1200.co...306_Photo_Index Maybe there is something there to guide you as to what to remove. The main fuel page on Datsun 1200: http://datsun1200.co...ory:Fuel_System

 

Len

[LenRobertson]

Regarding the wires around the carb, I don't know if the Hitachi for the A -series engines had an anti-dieseling solenoid, but you might look for that and test it. I always thought if that malfunctions it kills the idle completely, but maybe in reality the engine just start sucking gas from up by the venturi. I think the Datsun 1200 links I just posted should show where the solenoid is (if you have one).

 

Len

[ggzilla]

Tha anti-desiel solenoid is also called.the.idle-cut solenoid. It cannot cause excess fuel to flow. So concentrate on the basics . If idle is over 1000 rpm a lot of fuel will flow. Basics are float level, idle speed and idle mixture.

[Kisor]

Do you think it could be the solenoid is bad and the fact it is pulling fuel through the venturing being adjusted way out of wack to get it running at all?

 

Take out the anti dieseling valve and remove the pintle. Screw it back in and see how it does.

[az_rat210]

I would suggest pulling the carb, cleaning it and applying a rebuild kit.

The problem could be the accelerator pump leaking (missing the little steel ball), a leaky gasket, a stuck fuel cut off valve where the float attaches (seen this one myself, it was loose).

[Zeusimo]

You Are Having The Same Problem I Am Having

Car Probably Gets Around 10MPG

Only Runs With The Mixture Screw At The Bottom And Choke On

Runs Really Rich And Smells Like Crap

No Bottom End Torque At All

But Runs Really Well Over The 2K Range

 

I Tried Rebuilding It But No Luck...

[kelowg]

idle cut off, test it.

[JAS]

Checked the anti diesel solenoid, removed the valve guts... Still intermittant bad/good. Took the top off and the idle rich valve, blew everything out and bowl, then liberal passage cleaning with carb cleaner.... Blew out again, saw the ("power jet"?) Center, almost bottom bowl between the throats flop around in the compressed air breeze... Tightened it up a few turns to snug... About to put it back together now. Don't want to loan my 74 B210 to her to drive to work.. It has a dogleg, and can see what happens at stop signs...

[JAS]

That fixed it, 1/3 of a tank of gas to get it right. Thanks for all the help... Ended up being the power jet about to fall off in the bowl. Tightened up, and all is well. Loose enough to drain the bowl really.

[LenRobertson]

Great news you found the problem. Things like this drive me crazy, even when it is not my vehicle. I guess it bugs me how little I know about all this stuff.

 

A thought - If all that gas was going down the carb throat, I wonder if much could have gotten past the rings and diluted the oil? You might pull the dipstick and see if you can smell gas. Hopefully it didn't happen, but an oil change is pretty cheap insurance if you do smell any gas.

 

Len

[JAS]

Its always something different, never easy. The oil is fine, no smell there, I am carb retarded, I am great on Z car fuel injection. Now I am much better at carbs.

[ggzilla]

Now you are a carb expert, id say.