Engine idling at 3k RPM, I think I’m getting too much fuel from the carbs

[bravemushi260z]

25 minutes ago, Patcon said:

Let us know what you get

Quick question before I get into it tomorrow morning, I'm wondering if it could be some other issue with timing or something? This is my first time running this engine so I am not sure. The thing with the idle is, although it is high at 2500 rpm, it is not rough or jumpy at all. It holds it pretty steadily. What do you think? Also thank you so much for helping me out!

[Zed Head]

Throttle means to choke off, or cut supply.  The engine will spin as fast as the air supply will let it.  It's controlled by the throttle because the throttle controls the air supply.

https://www.merriam-webster.com/dictionary/throttle

Edited May 2, 2021 by Zed Head

[Patcon]

Timing might determine smoothness but Zed is right. You're very likely getting too much air. The place to start it to remove the linkage from the pedal to see if the blades can close some more

[bravemushi260z]

Okay I think I understand what @Zed Headbetter now, so I’m getting too much air that’s causing it to run rich, so I’m thinking that could be either a vacuum leak(but I’m not sure since it’s not running rough just idling high). The other likely culprit could be that the carb wasn’t running choke plates ? When I rebuilt the hole for the choke shaft was welded close. I’m headed out now to check the linkage 

[bravemushi260z]

Holy crap guys it’s perfect now, it was just the linkage!! I readjusted it and now I’m idling at a smooth 800-1000. (Atleast I think so, my rpm gauge decided to stop working all of a sudden LOL). It also had a ridiculously loud exhaust for a car that’s actually pretty slow. Thank you so much for all your help!! 

[Patcon]

Good job

[heyitsrama]

22 hours ago, bravemushi260z said:

I don’t have a fuel return line, the previous owner removed it. Do you think this could be causing my issue??

Well you fixed the problem, but the return lines were added because of heat soak that can occur, this causes the fuel in the fuel rail to vaporize and prevent it from getting into the carb.
 

Did they remove the whole line? It’s a bit of a pain in the arse to get to the whole thing, I’d be surprised.

[bravemushi260z]

1 hour ago, heyitsrama said:

Well you fixed the problem, but the return lines were added because of heat soak that can occur, this causes the fuel in the fuel rail to vaporize and prevent it from getting into the carb.
 

Did they remove the whole line? It’s a bit of a pain in the arse to get to the whole thing, I’d be surprised.

@heyitsramaI believe they did, I had bought a kit with all the fuel lines and am planning to install them, but I think I’m going to need a new fuel rail for the return, here’s a picture of the setup right now, and you may be able to see it better in the video I posted earlier.

[heyitsrama]

Some cars don’t have a fuel return line, what year is the car? 
 

dustyyyyyyyy or as some people say “patina”

[bravemushi260z]

1 hour ago, heyitsrama said:

Some cars don’t have a fuel return line, what year is the car? 
 

dustyyyyyyyy or as some people say “patina”

I know I’m cleaning it up haha, it’s It’s been sitting outside in Colorado for years. It’s a 74, it definitely has one I see it capped off with a bolt on the passenger side. Really not sure what the previous owner was trying to do. 

[bravemushi260z]

On 5/2/2021 at 10:34 AM, Patcon said:

Good job

It was all going well for a while but now I have the same issue, it's not being fixed by the linkage any more. I'm thinking it might be caused by a vacuum leak but i checked everywhere and don't know what else to check to be honest. Carb adjustment doesnt make any difference. I am at a point where I might just buy some new carbs to be honest. Or just go EFI

[Racer X]

2 hours ago, bravemushi260z said:

It was all going well for a while but now I have the same issue, it's not being fixed by the linkage any more. I'm thinking it might be caused by a vacuum leak but i checked everywhere and don't know what else to check to be honest. Carb adjustment doesnt make any difference. I am at a point where I might just buy some new carbs to be honest. Or just go EFI

Have you checked for vacuum leaks?

If so, how?

 

Changing carbs, or going EFI, is following the same route as the guy who put the Webers on did. I know, the Webers replaced those pesky flat top Hitachi things, but the flat tops can be made to operate correctly, give the proper maintenance and adjustment.

 

Your car looks like it has been neglected for a considerable amount of time. Get rebuild kits for the carbs, and replace the intake/exhaust manifold gasket. Put the fuel return back into the system. 

Then adjust and tune the carbs.