Rough idle issues and Carb gaskets

[chope97]

Today was a beautiful day in the D.C. area. I drove my car to the exhaust shop it drove well and it was nice and fast but the idle was not good. When I got back I decided to check the timing. My car has no ball or marks on the fly wheel that can be seen from the little hole. I adjusted it by ear and watched the idle go up or down on my sears tune up box from the 70's. It was running better but not where it should be, next I decided to check the cabs to see if they were in sync. Turns out they were a little off but I could not get them to adjust. I decided to spray some carb cleaner at the base of each carb by the spacer. One carb got no reaction. The other carb by the firewall caused the idle to go way up. Question, I have taken the carbs off before is there something better than the cardboard gaskets I can use that will seal better? Should I use two gaskets together? Should I use gasket seal?

P.S I also found that the on the manifold closes to the firewall the vacuum port that had a cap on it the cap had come off so this was causing a big problem also

 

[boonies]

Usually one paper gasket is enough. I would check to see if the surface is cklean and the crb base is flat. Once you have the vacuum cap back on you should check again and pay attention to the throttle shaft area.

You may want to clean and lubricate the linkage so that each carb can be adjusted to come off the fully closed throttle plate together.

 

[dbower]

Jam Engineering has gaskets for most Webers, if that's what you have.

 

[chope97]

thank you , I have done , I will check for a flat carb base. I sprayed right on the spacer

 

[chope97]

Jam Engineering has gaskets for most Webers, if that's what you have.

I have 32/36 dgavs

 

[stphers]

Also, check the throttle shafts to make sure that they are not leaking I am doing both carb base gaskets with webers on a 3.0cs right now Pierce manifolds carry them as well

Thanks, Rick

 

[alprada70]

I sell a gasket set for Zeniths

 

[Sven]

This was a common problem with the Zenith's. 40+ years ago I used a wet/dry sandpaper on a piece of glass to sand the cab bottom mating surface perfectly flat. Same with the spacer blocks.

 

[Ohmess]

Sven's suggestion is a good one for the Webers as well. Pierce manifolds lists the gasket for your carbs: https://www.piercemanifolds.com/BASE_MOUNTING_GASKET_99005_068_p/99005.068t.htm

 

[bluecoupe30!]

Yep. Agree with Sven. I have 2-32/36s on my M30, and went through all this vacuum leak stuff and sundry other gremlins several years ago. Tightening down the mounting nuts did not help me feel I had taken up any gaps at the carb base. And these Webers are old! So, removing both carbs, placing them on sheet of glass, sanding just a bit, then using a light to see if there was still any leakage, then finally removing a bit more material. New gasket, and finally a satisfactory fit. I will add that I also replaced the throttle shaft bushing in both carbs as this is a typical wear/leak area. Good luck, and let us know what worked.