Demon problems

[jerebus67]

I am not too technical but wanted to see if anyone else has this problem and any suggestions? I have a ZZ4 crate motor and purchased the 650 Barry Grant carb for it. We have had nothing but problems setting the carb up. It idles well and runs ok but it seems like the low end power just isnt there. When putting the car in the garage after I drive it the garage just stinks of gas. I am thinking about pulling it off and putting an edelbrock on it? I would really like to obviously tune this carb so if anyone knows anyone in the Bloomington IL area that is good please let me know.
The garage stinks up the whole house, any idea why it is so rich?

[Travis B]

What kind of shape are the power valves or valve in?
Float level fron and rear???
What do the plugs look like after idling for awhile, is there any black smoke or hestation off idle??

[jerebus67]

We have been through 2 sets of plugs since we put it on. We havent had a problem for a month or so now. Any suggestions?

[Travis B]

What plugs are you running! Was carb new when it was put on....

[jerebus67]

Regular stock plugs, New carb, new ZZ4

[Matt@RFR]

Well, first of all, put some real spark plugs in it like NGK's.

Yeah, check the power valves. Suck on the end opposite the spring and stick your tongue to the opening...if it holds vacuum, it's good. And gas tastes good.

Demon carburetors are NOT Holleys! They don't tune anything like a Holley....in a good way. They are VERY sensitive, and need to be tuned accurately, and in very small steps. As an example, don't turn the idle mixture screws anymore than an 1/8 turn at a time.

Set transfer slot exposure to .040" primary, .020" secondary, and as you adjust curb idle mixture and the idle speed changes, use BOTH primary and secondary curb idle screws to adjust RPM. Again, this is very sensitive.

You may have to change the idle air bleed size too. We've had to with every Demon we've run. They sell press-in restrictors if you need to go down in size, but if you need to go up in size you have to drill them out.

If you get this far into tuning, I'd suggest getting the Demon book. It's pretty thourogh.

[SS396]

Check the Metering block on the primary side..Their should be 2 pen size holes in the top of the block (main well) MAKE sure their are Brass plugs sunken in EACH of the main wells ...

With the car off .... Spray some Carb clean into the Pimary booster careful not to get a face full of carb clean Do to the Missing Plugs in the Primary Meetring block ...Like i got


Last Year I bought a brand in sealed box 750 Speed Demon from a major mail order speedshop ..

It would ideal fine but stumble on part throttle then pick up after the secondary opened ..I fouled many sets of plugs plus pulled my hair out for a week .I tried every carb trick i knew called their tech line, bought the book (Did everything Matt@RFR posted above ) .till i did what i listed above

The pepole at BG had me ship my carb back to them (They didn't belive me ) Anyway 2weeks and many phone calls latter i got my carb back with the missing plugs installed ..Carb has been spot on since ..

BG said Sorry it was a freak thing and paid the shipping ..Would have been nice to get the money back for all the spark plugs i wasted

Hope it help's
John

[Steve1968LS2]

Calling the mfg is usually the first and best step when you have a problem with a part..