625 road demon tuning??

PickupMan

Founding Member
Jan 30, 2000
403
7
28
Hazleton, Pa
I picked up a 625 road demon card for my 289. The carb is brand new just the guy couldn't tune it so I picked it up for next to nothing. Anyway I installed it on the car today and got it to run but for some reason it idles way too rich and the car will stumble when you go to pull out. Also if you run first gear out and hit second and floor it it hesitates for a second then it will come back to life. I set the floats and tried to adjust the ?bleed air screws? on the side of the metering block but when you turn them all the way in the idles just goes up?? I thought it was supposed to stumble if they are turned all the way in? Any ideas on what it might be? The carb really makes the engine come to life but I'll throw the ole holley 650 back on if I can't get it squared away.

Thanks guys
Joe
 
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sounds like an internal fuel leak to me. if you can turn the idle mixture screws all the way in and the engine stills runs that is an internal leak. replace the metering block gaskets, and the power valve. also make sure that if the accerator pump circuit requires a tube between the metering block and the main body, that the tube is there and properly installed.
 
Thanks rbohm:nice: I just got done reading some info from the demon website and found some things that answed my question...should have researched prior to asking:bang: One thing they said was to adjust the floats again..I had them set a little too high and reset the butterflies. I had the carb apart prior to installing it and replaced the gaskets. I'll try it tomorrow and see what happens. Thanks again!
 
ah so you got demons bad apple too. i know the stumble your talkings about at wot. the transition circuit in the secondaries are super lean or dont work at all. theres no easy fix for this if one at all. i did figure out a work around for this though. in the secondary linkage, i put a bolt thru the sloted part to open the secondary plates about 1/4 when the primarieas area at full. this gets you past the bad spot.
 
Mustang Matt I haven't had a chance to work on it yet. Going to see what I can do today.

Ashford,
Once I get the little things with the carb squared away i'll try your trick. yes it's a very odd thing it does for having vac secondaries. With the engine at 5500 rpms and hit second gear that carb shouldn't even come close to hesitating but it does...like a bog!! I was going to try a stiffer spring to see if that helps. I'll fill you in my progress!!

thanks
Joe