Carb idle adjustment ? DEMON
 

Well first run to day did good but engine loads up driving down the canals. To the point it will not idle and wants to die (or dies). It is a 650 sea demon carb that has the four corner idle screws. My dad played with the adjustments but he is on vacation and I would like to use the boat!!! What is the best way to set it up. It ran great on plane.

Re: Carb idle adjustment ? DEMON
 

650 cfm must be for a small block motor?

The idle screws should be 1 to 1 1/2 out . You want to adjust them the same front and rear to get the highest idle . I use to adjust mine while in gear.Screwing them in should lean it out.

There could be other things making it foul . A piece of trash in the needle and seat . Fuel pressure to high . float level,There should be adjustment on the rear throttle blade also.The front and rear should have the same amount of transfer slot showing . this is underneath the carb.

Once the plugs get wet fouled they usually want run right . the gas soaks into the porcelain

maybe this will get ya thru the weekend?

Rob

Re: Carb idle adjustment ? DEMON
 

What psi should I be at / my gage reads around 5.5 - 6 and yes this is a small bolck.. I will give it a try thanks.

Re: Carb idle adjustment ? DEMON
 

usually 7 1/2 psi

Re: Carb idle adjustment ? DEMON
 

7 1/2 is pretty high for a SBC.....5-6 psi is just fine.....

Re: Carb idle adjustment ? DEMON
 

don't the demon have a idle adjustment on both sides?
(one in the front and the other in the back)my 950 did (not sure on this one)but if it does you have
to adjust both side when you set the idle

Re: Carb idle adjustment ? DEMON
 

Whould a bad power valve cause this problem?? It took around 8mins of idling down a cannel to start to mis and foul the plugs. My dad had the idle scews set different back two were set richer..... I have them set at 1 1/2 turns out I will see how it goes....

Re: Carb idle adjustment ? DEMON
 

Correct adjustment is not a set # of turns.....Hook up a vaccumn gauge. Adjust the mixture screws till you get the most vaccumn and then reset your idle speed and try again....go thru this routine till you get your idle where you want it and have the most vaccumn