# High RPM after Carburetor Rebuild



## TX1967GTO (May 14, 2015)

Hello All,

I'm new to this forum. I love classic muscle cars. Working on my 67 GTO, and I'm a little stuck. Any advice is appreciated...

I rebuilt my Edelbrock 1405 (600CFM) that was on my 1967 GTO 400 engine. After I installed it and fired it up, the idle is around 1500 RPM. Actually bought a new 1407 Edelbrock 750CFM thinking I messed something up during rebuild. Same thing after installing the 1407, idle at 1500 RPM to 2000 RPM. Didn't touch the distributor or anything that could mess up the timing. 

Any idea what I did wrong? Any advice is much appreciated.

1967 GTO, 400 engine with TH400 transmission. To my knowledge, everything is stock. 

Thanks,


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## Lemans guy (Oct 14, 2014)

Well maybe the idle jets on that old one we're all gunked up!

So RPMs at idle, start with temp....is this hot? Or cold?

If cold choke operation and the fast idle screw come into play and they have to be set right...your old choke and fast idle screw setup could have been a little different..

If this is hot, all warmed up 1500 RPM's than you have to adjust the mixture...and make sure that you fast idle screw adjustment is totally out of the picture and not holding open the throttle plate.....

Now this is just general carb stuff as I don't know that exact carb and some adjustments Amy be different....

Fuel pressure also come into play, but it. Should be a slight adjustment ....but hot or cold matters....atriot:


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## TX1967GTO (May 14, 2015)

Appreciate the response. Fast idle screw was off. Also, the throttle cable was too tight.


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