having trouble with a demon

[N20Jeep]

ive got a demon 750 on my engine, and i cannot seem to get this thing to stop running rich. it is constantly fouling out plugs. and whenever i do get it running smoothly it only last a few days, then begins to run like crap again.

 

any hints on tuning these?

[grumpyvette]

first step is verifying the fuel pressure is in the 4-5.5 psi range and the floats are correctly adjusted, a RETURN STYLE fuel pressure regulator with a byepass line back to the tank is almost MANDATORY for maintaining consistant fuel pressure, and having a gauge to check/verify not guessing IS MANDATORY

Edited March 14, 2009 by grumpyvette

[N20Jeep]

ill have to check it when i get back to the house...i think last time it was running the gauge was around 7-9 psi

[grumpyvette]

7-9 psi will almost always overcome the needle & seat and constantly flood the carb, that is probably the source of your major problem, install a RETURN STYLE fuel pressure regulator, and a line back to the tank or at least back to a TEE thats located befort the pump intake point

 

http://www.jegs.com/webapp/wcs/stores/servlet/category_10001_10002_10019_-1_10267?sendroicid=bbef8492-2d00-41d6-b158-38db0de2603c&sendroiad=3824188001&sendroikwd=Fuel+Line&gclid=CNrLsez3opkCFQudnAodtC_cpQ

 

 

 

these cheap ones, that are dead head style seldom work well

 

http://www.jegs.com/p/Holley/745059/10002/-1

 

much better

http://www.jegs.com/i/Mallory/650/4307M/10002/-1

 

http://www.jegs.com/InstallationInstructions/600/650/650-4307M.pdf

Edited March 14, 2009 by grumpyvette