Tunning 625 demon idle

1987StangL268X · 03-06-2007, 11:26 PM

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!

Rev · 03-07-2007, 10:24 PM

Quote:

Originally Posted by 1987StangL268X

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!

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

1987StangL268X · 03-07-2007, 11:52 PM

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

93svt · 03-11-2007, 12:27 AM

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.

03-06-2007, 11:26 PM	#1
1987StangL268X Registered Member Join Date: Feb 2007 Location: Tennessee Posts: 38	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! __________________ 1987 mustang hatchback. weld wheels, driveshaft loop, subframe connectors,308 w/ 520 lift cam, edelbrock perf rpm alum heads 2.02 1.60 valves, 1.6 roller rockers, edelbrock air gap performer intake, roller lifters, 625 vac secondary demon, c-4 trans w 3,000 stall, 3.73 gears

03-07-2007, 11:52 PM	#3
1987StangL268X Registered Member Join Date: Feb 2007 Location: Tennessee Posts: 38	Re: Tunning 625 demon idle thanks, will try it! I have heard demons are a job to tune good __________________ 1987 mustang hatchback. weld wheels, driveshaft loop, subframe connectors,308 w/ 520 lift cam, edelbrock perf rpm alum heads 2.02 1.60 valves, 1.6 roller rockers, edelbrock air gap performer intake, roller lifters, 625 vac secondary demon, c-4 trans w 3,000 stall, 3.73 gears

03-11-2007, 12:27 AM	#4
93svt Registered Member Join Date: Aug 2006 Location: Yankton SD Posts: 27	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.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
New cam, tunning again	88workcar	Windsor Power	9	11-17-2003 06:15 PM
tunning my 5.o?	whitepony	Windsor Power	1	09-03-2003 02:46 PM
Speed Demon vs. Road Demon	86GT	Windsor Power	1	01-20-2003 11:33 PM
tunning ?	302crew	Windsor Power	5	10-16-2002 01:39 PM
NO MORE IDLE SURGING! Success with the SURGE DEMON!	gtsr515	Windsor Power	10	05-10-2002 06:54 AM