Carb. help

[_chiefjt]

My first carb. rebuild. 1986 Nissan 720 z24 with all those crappy plugs to the carb.

 

 

So after all my break downs and BSing the carb. I finally rebuilt my stock carb. on my Z24. I took it off bought the cleaner and took it all apart and soaked the bare carb. pieces. After everything was cleaned I put it back together with all new gaskets, accelerator pump and what not. So I put it back on and it started and ran better than before but the throttle linkage thing was sticking so it made it run very high. It wasn't idleing. So I pulled it back off, made some adjustments that were wrong and it is now going back all the way and pushing the idle up control valve. So I put it back on and got it to idle but it idles so low it wants to die. But when it warms up it idles very smoothly like nothings wrong and accelerates very quickly. The float level shows up on the glass but is not at the center. It's in the middle of the bottom of the glass and white dot. It might be my choke I'm not sure if my choke is even right so if I can get a picture of one that is that'd be great.

[P.Rubber]

Mine did the same thing. When I did a full tune up the timing was off 10 degrees or something. I got my timing where it should be and it helped. Mine still wants to die at cold start but i haven't got to that yet

 

[I'm BLUE]

yup pictures would be helpful !

 

Indeed ,,, check that choke !

 

Do spark plugs tell you it is rich or lean ?

 

Have you adjusted your idle circuit lately ? If so procedure ? :)

 

Have you checked for vacum leaks since repair/rebuild ? ( with fire extinguisher in one hand or next to self ,,, take a can of carb clean ,,, very lightly mist sealing surfaces and vaccum hoises along intake manifold/carb/etc ,,, if idle speed INCREASES you have a vacuum leak at that location ,,, if no increase ,,, you are good ! )

 

Check all your vacuum hoses as well ,,, don't be fooled split vacuum hose ends on the inside cause leaks even though they look great from the outside !

 

 

( good on you for using carb dip ! yes !!! )

[_chiefjt]

A tune up does sound nice. I pulled my plugs before all this but I only checked the exhaust side. They came out black. And how do I adjust my idle circuit? I bought it at 174,000 miles and the engine looked like it's never been taken apart or carb rebuild. So probably does need a idle circuit adjustment. When I got it it didn't run but I looked at the diagram on the hood and all the vaccum lines were crossed and looked like noodles. But I got all new vaccum lines and have all in the right place. But I want to get rid of them and just plug everything up. haha

 

So yeah, How do I adjust my idle circuit and if it doesn't work I'll do a tune up and check the choke again.

[_chiefjt]

@P.Rubber : The difference is, I live in Vegas where it's over 100 degrees. LOL

[Meticulous]

i recently had similar issues with an Hitachi for my 210, couldnt get it to idle, figured what the hell and bought a weber, this swap eliminates emissions like you want and is a very simple fix to alot of problems but it does cost around 350 after its said and done.

[Meticulous]

looks way cleaner under the hood!

[datzenmike]

The Z24 carb idle speed is set at the factory and then sealed. If you look on the very bottom pass side you'll see an aluminum plug covering it. You can drill a small hole and pry it out so you can get at the mixture screw, but this will cause problems if you have smog inspections. I would try to solve the idle problem first and do this as a last resort.

 

Take the air filter off on a cold motor and look down the carb. The choke plate should be open or mostly open. Pump the gas peddle... the choke plate should snap shut. This should engage the fast idle cam to rev the motor up with the choke on.

 

The plastic thing with the steps on it is the fast idle cam. The slotted screw with the nut is the fast idle speed adjustment screw. When the peddle is depressed the choke closes and the linkage drops down rotating the fast idle cam. The fast idle screw closes on one of the steps of the fast idle cam which holds the throttle open. When the motor is warmed up the choke comes odd and pulls the fast idle cam out of the way and the idle drops off the stem and idles normally.

[_chiefjt]

So I looked down my carb and the choke plate was fully open. I pulled the throttle underneath the hood but the choke doesn't close. Not even if i peddled it. The fast idle cam doesn't move when I throttle it. It doesn't drop down like you say so the fast idle adjustment screw never touches it.

 

Don't know what the problem could be.