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High idle, second test

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drooartz

drooartz

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I went out after dinner and played some more. After reading through the Haynes and factory manuals, I tried fiddling with the idle screws and the mixture screws. I was able to get the idle down. Don't know what happened, but I think it was just a bit out of whack somehow.

Now I'm trying to figure out how to get the SUs adjusted to normal running. The Haynes and Factory have slightly different methods. I'm having fun playing, even if I may be making a mess of things. I know I'll get closer.

Any tips for SU work would be appreciated!
 
Drew,

SUs are really fairly simple. The key to getting them set up correctly is to make sure you've set everything else to spec prior to messing with them - timing, point gap, spark plug gap, valves. Then set the mixture - I have a Colortune, but usually set them using the Haynes method - lift the piston slightly and listen for an increase/decrease in RPM. Then finally you need to sync them. If you don't have a carb sync tool, you probably need to get one.

I'm a firm believer in the old adage that 90% of carburetor problems are electrical.
 
After a couple hours fiddling with the carbs, I have a theory about what might have happened. I was able to get the idle back down, and get things synced. I think I have the mixture right now as well, but not really sure.

Right before I noticed the idle issue, I may have given a quick blip to the throttle. If the connecting clamps that hold the throttle bar/pipe thingy together weren't totally tight, it might have moved one carb just a bit more than the other. When the throttle came back, it wouldn't return all the way since one of the carb set screws would now be too high.

I noticed this because when I had things close and first tried to retighten the little clamp-y-dos, The car ran high again. I had to hold loosen things up and hold down the carb screws to make sure they didn't move while I was tightening the clamps. It's a thought, at least.

I've got some more twiddling to do, but I think I'm getting a better idea of how those suckers work. Next I want to gap the points and set timing, then I'll get back to the carbs and try again.

I'm having fun! /ubbthreads/images/graemlins/grin.gif
 
I suspect you found your problem. Yep must be tight and tightened after carbs are set for idle.
 
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