Hi all..
My continuing saga. Background: previously wouldn't idle except with choke on at 2500+rpm. Would only start with the choke even when warm. Ran like general crap. What I have done: drained gas tank through coffee filter-clean. New fuel pump and now TWO inline new fuel filters. New dizzy cap, ignition modules, dizzy and spark plug wires, spark plugs. Shutter valve now PERMANENTLY open. None of that fixed anything to speak of. Just had my carburetor professionally rebuilt (National Carburetors) and now it will idle and restart without the choke once warm. The lowest rpm I can get is 1200, go any lower it dies. Drove it down the street and it did OK except when I take my foot off the gas and it's like it surges. The carb definitely did improve the previous issues. Sounds like it is missing or just not right at all (see-hear video). I adjusted the air-idle mixture screw to the point is was "choking" then opened it up 2 turns, but frankly, sounded the same the before and after (missing). Any suggestions/recommendations or just ell me I'm an idiot, would be appreciated. Mike

 

So while it was idling (I am so happy it at least idles now!), I sprayed carb cleaner around the base on all 4 corners. Lo and behold, on 3 corners (mounting bolt area), no change. Of course when I sprayed around “the evil” bolt, rpm’s went up immediately. Vacuum leak. Having read through literally hundreds of posts on here, the majority say do NOT use gaskets between the manifold and vacuum-spacer plate AND between the spacer plate and carb. So I didn’t. I have never messed with the spacer plate..I.e. never tried to peel back anything. It is smooth but I don’t know the actual “flatness”. I will assume it is not exactly level and air is getting in. So now I am trying to decide on whether to use gaskets (I have the ones with the vacuum port holes in them) or just use sealant and not cover any holes. Thoughts, recommendations? Thanks!! Mike

 

I would try cranking the bolt down more (carefully). Or if that fails use some spray on gasket stuff to try and seal it up.

 

Yeah, I have my “special” wrench I welded up just for that bolt. Can’t get any tighter, but he spray on gasket is a good idea! Thanks!!