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Tips
Tips

Su adjustment tips

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bugedd

bugedd

Jedi Knight
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I'm having an issue with my idle being too low and the car occasionally dieing on me, so I've been digging around on the internet and I can't find an idle adjustment screw. I see something labeled a fast idle screw, but thats the closest I can find. Can someone advise to a good site or tips on proper idle speed setup on SU's?
 
Fast idle screw is it! Good idea to make sure the SU's are adjusted and sync'd first.

Kurt
 
As novice with carb adjustments myself, I went ahead and spent the bucks to get a synchronizing tool (basically a vacuum gauge) and also picked up the Gunson Colortune spark plug to help me get the mixture correct. I've found both of these tools to be invaluable to getting the carbs properly synched and mixtures set right. As time goes by, I've become more conscious of how the engine sounds in various degrees of synchronization and mixtures. I could probably adjust the carbs without the outside aids by now, but since I have them, the really do take a lot of the guesswork out of SU adjustments. I do know from experience that when you completely miss on the carb adjustments the car is NOT going to be happy.
 
fortunately the car is pretty happy :smile: She is running strong, though feeling flat after 4k, but my old bugeye had a much hotter motor with a mechanical advance dizzy and Weber DCOE40. It got on it. Right now I just want her running solid for many road trips this year. Its pretty exciting, the old yeller car never made it out of town, I wasn't too sure of its capabilities.
So the fast idle screws.....there are obviously two of them.....just bump them both up the same amount to get the idle proper?
 
I'm not sure you are getting good advice here. there are two sets of screw for adjusting idle speed. One set is called the fast idle adjusting screws....these are the ones that contact the rotating cam when the choke is pulled (screw heads are pointed toward the engine and below the carbs). The other set is throttle adjusting screws....these two screws are for setting the idle speed when the car is warmed up (they are located next to the round suction chamber and the screw heads point straight up). Yes, once the car is warm, turn them clockwise both the same amount, a small amount at a time. good luck, Scott in CA
 
smaceng said:
I'm not sure you are getting good advice here. there are two sets of screw for adjusting idle speed. One set is called the fast idle adjusting screws....these are the ones that contact the rotating cam when the choke is pulled (screw heads are pointed toward the engine and below the carbs). The other set is throttle adjusting screws....these two screws are for setting the idle speed when the car is warmed up (they are located next to the round suction chamber and the screw heads point straight up). Yes, once the car is warm, turn them clockwise both the same amount, a small amount at a time. good luck, Scott in CA
Click to expand...

I agree with this. The fast idle screws should have no effect on the idle speed unless the choke is pulled out. If they are affecting the idle speed, either the choke is not completely off, or you have the screws too far in.

If you're having trouble distinguishing the two, the fast idle screws are oriented more-or-less horizontally; the regular idle screws are oriented vertically and closer to the intake manifold.
 
Got it, just fiddled with them and things are where they should be. This resulted into degreasing things under the hood, then the door jambs, then washing the car. Funny how things snowball.
 
nomad said:
Fast idle screw is it! Good idea to make sure the SU's are adjusted and sync'd first.

Kurt
Click to expand...

I was picturing the right screw's....just screwing up on the terminology!:apologetic:

Kurt.
 
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