I've got a Demon problem

[71chevylowrider]

I'm having some issues with my Road Demon 625, first, it is setup stock & runs way too rich, smells like raw gas fumes when it's running, but the more serious problem is that it has been sticking at a very high idle, like 2,500-3,00 rpm's so I jam the throttle pedal to try to kick it down, but it will usually end up in an even higher idle & I have to turn off the truck to keep it from over revving, but the weird thing is, after I turn the key to start it, without touching the gas pedal, it starts right up at it's normal idle, any ideas? I love these demon carbs, it made my truck alot faster, but this is rediculous. I also have problems with the choke butterflies closing shut even ehen the truck is warm.

[Sport/Truck]

Sounds like you need an exorcist. lol
FWIW I've heard lots of good stuff about those carbs.
s/t

[RACINJASON22]

I bought one a few years back and had nothing but problems! One other than yours was after I shut the truck off carb would continuosly leak fuel into the engine. I even tried rebuilding the brand new carb and a handful of other fixes nothing worked. I also have heard many GOOD thing about these carbs. My experiences just turned me off on them. There may be someone else that has better luck with them that can help GOOD LUCK.

[70c10]

I'm not smart enough to answer even though I love my Demon but I would try to totally disconnect the choke to rule that part out of the problem. Other than that I have no clue what to look for.

[71cheyennezz4]

I had the exact same problem with my speed demon series carb, i realized that my secondaries were sticking that was the problem, if you losen the bolts and move the carb and make sure that your secondaries arent hitting the carb spacer, mine were, after you do that close them and fill the entire carb with carb and choak cleaner, mine had some gum on the butterflies in which they werent closing, also you need to add a stronger throttle spring, and for the last one, on the throttle linkage you will see a small rod which opens and closes the secondaries sometimes a very small bend in this rod will ensure they close everytime i had to bend mine a little because when the throttle was released it wouldnt push them all the way shut, if you need any additional help my cell phone is (402)366-9181 i would be glad to help you anytime.

1. Check and see if the secondaries are hitting on the carb spacer if they are move the carb untill they are free
2.Close the secondaries and fill the entire carb with carb and choak cleaner and let it soak, do this 2-4 times.
3.Add a stronger throttle spring to make sure it closes all the way.
4.Adjust the rod that closes the secondaries by bending it.

[71chevylowrider]

Hey thanks for the reply guys, I am really stuck, I don't even feel confident in driving the truck now until I get this fixed, the other day it stayed at 3,00 RpM's & it was rainging & I had a bit of a hard time stopping at a light, I unhooked the power wire to the choke & nothing changed, the thought about the secondaries hitting the spacer is a good one, I'll check that out, I totally cleaned & soeaked the carb in carb cleaner before I installed it & it looked shiney & new, I like these carbs & would consider buying a new one even if this one is just a Lemon, the guy I bought it from said he changed it out to a Holy because it wouldn't hold a consistant idle, boy that is an understatement. I even tried it wih no air cleaner to make sure thats not catching on anything & no change.

What I don't get is the high idle 3,000rpms, will go away from just shutting it off & restarting it without touching the pedal.

[bryanw1968]

No worries man. You own IMHO the best carb out there.
I have had all of the same issues and it's because it's just not set up right, yet. Like mentioned above, especially if you're using a spacer, you're butterflies are getting hung up.

To make the choke work right loosen the three alan screws and turn the choke mechanism to the "-" sign and that will fix you up.

The thing is with these carbs is, they are very sensative as far as tuning goes. The air/fuel adjustment screws should be turned in 1/16th increments.
Holley's are made to work with a much broader variety of applications and are therefore you can't get them quite as dialed in. Not slamming Holley's, I like em'. But a Demon is just a different carb.

Anyway, I've had 3 demons and know them very well. Feel free to PM me if you can't get it resolved and I'd be happy to help you get er done.

Good luck!
B

[71cheyennezz4]

you also may have to cut your air cleaner pan, check www.barrygrant.com for more details on that, i had to do that because the choak was hittin on the air cleaner and it was holding it at about 2100 rpm

[71chevylowrider]

Yea, I did some mods to my air cleaner, but when this problem started happening I took the air cleaner off to make sure it wasn't sticking on the butterflies shaft, it still has the same problems.

[71cheyennezz4]

the next step, email or call demon about it, they are geat with technical support and tuning issues.

[71chevylowrider]

I e-mailed them yesterday & havent' heard back yet, I'm about ready to chuck it & buy a new carb.

[71cheyennezz4]

dont chuck it, send it to me if you dont want it

ill pay shipping

[71chevylowrider]

I only paid $150 for it so I can't complain too much, but if I do buy new I'll let you know, I'm kinda leaning towards the speed demon.

[bryanw1968]

That's what I run and I love it!!!!!

[71chevylowrider]

Hey 70C10, I think this is the forst time I ever posted a question & you didn't have the right answer for me,

you got the flu or something?

I forgive you 100% You have had great advice/info for me in the past & i really apprecite it.

[cooters]

I never ran a demon but never heard to many good things about them

[LockDoc]

-
I bought a new Road Demon Jr. and put it on my '39 Ford coupe a year ago and I have never been able to get it dialed in. I called Grant once and the guy I talked to kind of brushed me off so I never called them again. I'm still fighting it.... It ran better with the Quadrajet on it....

LockDoc

[71chevylowrider]

wow, it's like you either love em or hate em, all I know is the truck way faster with the demon then it was with the ol "reliable" edelbrock 1406, I'd like to get it working good, cause when you get on it, it makes my 4,000 pound truck feel very light & quick on it's feet, & it will fry the tires even when your going down the road on dry pavement.

[cooters]

i find alot of demon and holley avenger series carbs make good power but dialing them in for daily driving is difficult or impossible, they have 2 possitions, idle and full throttle

[lilpup69chevy]

i had tried a race demon on my buick 455 race car, what a joke had nothing but trouble with it and the quadrajet i had built was a lot better, ended up with a q jet back on it until i got a 850 dbl pumper dialed in for it, all in all i was happier with the q jet

[71chevylowrider]

Dang, I am no carb guy either, I was happy that I could bolt it on & get it dialed in to haul a$$, but if Demon take a little tinkering all the time, I may have to re-think my carb choice, fast is fun, but reliability is very important.

[72step]

This is the first I hear anything bad about Demon. A friend of mine who's a mechanic bought a road demon for his car and told me it was superior to any carb he's ever had. I have a brand new Speed Demon on order from a local Demon Dealer, and he swears by them. He said once you set it, you're done, and should never have to mess with it too much. He also said that out of over 5000 which he's sold, only one has had to be sent back. The guy is a performance marine engine builder, and he's seen good horsepower gains on the dyno with just a simple bolt on of a demon. Obviously the guy who sold it to you knew something. Maybe he messed it up some how?

[RACINJASON22]

I thought I just got a lomen. Sounds like other as well. I do know people that have run them with no problems, but I have worked on alot of carbs and like I said before.-

even tried rebuilding the brand new carb and a handful of other fixes nothing worked.

Maybe there's quality issuses at the factory???

[71chevylowrider]

Hey thanks for all the great replies, I really appreciate it, my truck is too nice to have it running like crap & flooding & now the high idle crap, i do know the Demon I bought is several years old, so maybe it was a bad one from the start, who knows, I just need as much in put from people who use them to help me make a decision, I know the edelbrock I used to have was reliable, but man this Demon when it was working good made my truck so much faster it's amazing, I'm thinking about a Speed Demon, I just don't want to have to keep tuning it.