I have a 750 demon and it is letting fuel get into the vacuum port and go through the vacuum hose and into the vacuum advance on the distributor. This thing is sucking but still gas is getting in there. What is the problem? I'll probably post this in the carb board also.

 

only thing it could be is an internal leak in the carb

 

I emailed demon and here is there response.

A 750 Mighty Demon would seem large on this type of combination,
you can try the following to help out with your situation. You'll want
to put a 4-hole base gasket between the carburetor and your intake to
stop the fuel from getting into the vacuum lines. You'll need to
increase your initial timing to about 15 or 16 degrees BTDC. Set the float
levels at about 1/4 of the window. Start out with your idle mixture
screws at 3/4 of turn out.

Thank you

Tech @ Barry Grant, Inc.

BG Fuel Systems, Demon Carburetion, Nitrous Works, & Rush Performance
Filters

 

Hmmmmmm...............

I doubt it. Fuel shouldn't be able to get in there regardless. I suspect that your vacuum advance canister has a ruptured diaphragm. Draw some vacuum on it and see if it holds. Use a vacuum pump or your mouth through a piece of vacuum line. If it doesn't hold vacuum- problem solved- you need a new vacuum advance canister.

 

I don't know if it has ruptured or not. I haven't checked yet. Since it is a Demon maybe that is just what happens. I have a new vacuum advance on the way. It'll be here tomorrow. I am going to try what the "Demon Tech" guy says and see what happens.