Demon Carbs quality control
Thread Starter
Drifting
Joined: Nov 2002
Posts: 1,951
Likes: 1
From: Shore NJ
Demon Carbs quality control
Ordered a new 750 Might Demon and received it yesterday via UPS.... my intent is not to slam Demon however, after setting all the adjustments properly (3rd Demon I've owned) I could not get the carb to stay idling, float levels, transfer slots, idle mixtures were fine....so I called Demon, spoke to a tech who told me to "take the carb apart and check for debris"....
sure enough their was aluminum shavings in the main body blocking flow and in the metering blocks. The carb is going back because I felt paying $500. plus I shouldn't have to take apart a new carb, who knows if I got all of the aluminum out, so much for the "quality control" tags on the carb..:
I know one can slip through the cracks but I could of done some real damage to my engine. I have owned several of these carbs and it seems I always find some "quality control" problem with their carbs out of the box. I called the tech today and told him what I found, it wasn't his fault but he was glad I called and notified him that Demon bases their success on their reputation, they make a good product, just make sure to check it out carefully before you install and fire it up...jmo
sure enough their was aluminum shavings in the main body blocking flow and in the metering blocks. The carb is going back because I felt paying $500. plus I shouldn't have to take apart a new carb, who knows if I got all of the aluminum out, so much for the "quality control" tags on the carb..: I know one can slip through the cracks but I could of done some real damage to my engine. I have owned several of these carbs and it seems I always find some "quality control" problem with their carbs out of the box. I called the tech today and told him what I found, it wasn't his fault but he was glad I called and notified him that Demon bases their success on their reputation, they make a good product, just make sure to check it out carefully before you install and fire it up...jmo
Last edited by 73jst4fun; Jul 8, 2006 at 07:02 AM.
Team Owner
Joined: Feb 2003
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From: Lake Norman NC
Originally Posted by bobs77vet
my only qyality control issue was that my 650 speed demon turned out to be a 750 speed demon???? who would have thought that?
Instructor
Joined: May 2006
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Originally Posted by 73jst4fun
"take the carb apart and check for debris sure enough their was aluminum shavings in the main body blocking flow and in the metering blocks. The carb is being today because I felt paying $500. plus I shouldn't have to take apart a new carb, who knows if I got all of the aluminum out, so much for the "quality control" tags on the carb
I heard this very same thing from a friend who found machining debris in his new Demon. Thought it was just a fluke, now maybe not.
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From: Corsicana, Tx
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Pretty common complaint with Demons. They've had the problem for years but don't seem too worried about it. Heck they have you to do it for them for free!
JIM
JIM
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Melting Slicks
Joined: Dec 2000
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From: Wichita, KS
I have 2 Spped demons. I could never get one to idle below 2,000 RPM. After jacking with timing and carb. for days I finally took the carb. apart and found that one of the idle passages had not been drilled!
Thread Starter
Drifting
Joined: Nov 2002
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From: Shore NJ
Originally Posted by litevette
Great! All of this comes out now that I've bought one. a 750 cfm carb is 750 cfm, the tech says they flow more, that statement has always bothered me. So if your nor running a demon with no choke tower for better air flow what's everyone using? Holley hp, pro series, Quick fuel carbs...???
Racer
Joined: Jul 2004
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I had a 650 Mighty Demon on my 355 that I set one time and never touched in two years - thought it was great.
So, I bought one recently for a newly built 406 - a 750 Mighty Demon. The motor was tuned on a dyno with two carbs - a fully prepped Holley 800 (this is the engine builder's, "dyno carb" and is race prepped, and an out of the box 750 Mighty Demon. Both carbs idled and ran well, especially given the decent size cam. The interesting part was the Mighty Demon, with no modification made within 2 hp of the prepped and proven Holley 800. No problems so far.
So, I bought one recently for a newly built 406 - a 750 Mighty Demon. The motor was tuned on a dyno with two carbs - a fully prepped Holley 800 (this is the engine builder's, "dyno carb" and is race prepped, and an out of the box 750 Mighty Demon. Both carbs idled and ran well, especially given the decent size cam. The interesting part was the Mighty Demon, with no modification made within 2 hp of the prepped and proven Holley 800. No problems so far.
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I have a 650 double pump speed Demon on my 61 383. 4 years and I haven't had to touch it since I put it on.
A Holley on my 65 for years and I am constantly tinkering with it.
Q-Jet on my 68 427. It runs super, is fuel efficient but the primaries are way too small for great performance. You really need to open those big secondaries to get the performance.
Of the three, the Demon is the better carb without question. Smooth power delivery and absolutely reliable. I've recommended it to several friends with Vettes and they agree it's the best carb they ever had.
A Holley on my 65 for years and I am constantly tinkering with it.
Q-Jet on my 68 427. It runs super, is fuel efficient but the primaries are way too small for great performance. You really need to open those big secondaries to get the performance.
Of the three, the Demon is the better carb without question. Smooth power delivery and absolutely reliable. I've recommended it to several friends with Vettes and they agree it's the best carb they ever had.
Safety Car
Joined: Nov 2002
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From: out of nowhere
Originally Posted by Kalway
You should know better than use anything but a q-jet anyways.
Safety Car
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From: out of nowhere
As usual, there's mixed results posted here. I geuss I'll just have to find out. Unfortunately I don't know carbs so if anything has to be adjusted/drilled/reset I'm gonna have to fork over some more dough!