Tunning 625 demon idle
 

I have a 625 demon on my motor, and being use to holleys i do not know how to adjust the idle rich to lean? Anyone that has a demon or knows how a demon works please tell me! What are your current jets also??The car puts out a little gas smoke at idle its fine when driving. New plugs it runs good, then when they get carboned up from it idleing rich it starts runnning like crap!

Re: Tunning 625 demon idle
 

The Road Demon has 4 corner idle. There or 4 idle mixture screws, one for each ventouri. start with each screw about 1 1/2 turns open. Put a vacuum gauge on the manifold vacuum port. Gradually turn each screw in and out until you get the highest vacuum reading. The 4 screws should be at the same amount of opening. Keep the idle at around 750 rpm. That highest vacuum reading at the 750 rpm should get you the best idle. Sometimes I have to run slightly richer than that to get the car to cruise well as the car generally cruises running mainly off the idle circuit. But this technique should get you close to the best idle mixture.

Rev

Re: Tunning 625 demon idle
 

thanks, will try it! I have heard demons are a job to tune good

Re: Tunning 625 demon idle
 

I have had 1 625 Road Demon Jr and it was picky on float setting, couldn't go by the standard Holley "bottom of the plug" float level. Just an idea.