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Join Date: Jul 2000
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Re: High idle in park
All this is without the vacuum advance hooked up and the hose plugged.
Adjust your idle speed down (screw on drivers/side of carb) as low as you can without it stalling in park then adjust your idle mixture adjustments (with a vacuum gauge attached hopefully) on the sides of the carb try to get it to idle smoothly to about 500-700 RPM then adjust your timing to about 10-18 base timing this should get it to idle better and a little faster.Then go back and re-adjust the mixture screws,if need be.
Be prepared to go back and adjust everything again if your starting points were way off.You're looking for about 750 to 850 in drive,as a starting point.
That idle speed screw on the D/S can cause more trouble than you think.Yes cranking it down keeps it running but at the expense of the carb idling correctly.If the engine is idling too fast the timing gets screwed up because its already advancing with the distributors centrifigal advance. Thats why adjusting the carb idle mixture and idle speed is important.
There are plenty of carb adjustment tutorals here on TC.Also Holley carbs has some more advanced tutorals to go by.
When all is done and its idling properly then you can decide between manifold vacuum advance or ported vacuum advance.Each has its own merits and either one can be right for your particuler combination.
Forgot to mention you may also have to adjust the float levels in your carb if they're way off.
71 El Camino SS
406 SBC M21 3.31 12 bolt
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