power valve question

[slimbo]

the only way fuel would be coming out of the boosters at idle is if the floats are too high or the pv is torn. if you have a mech only advance sometimes they stick when returning back to idle which in turn keeps the idle high until it returns to the initial timing and then the idle drops down. my car also has a slight hiccup if i run it real lean at idle. some motors just wont run like that.

 

[holtjohn]

but the advance sticking wont cause his very rich condition at idle. I think that is the main thing he wants fixed.

 

[slimbo]

The leanest mine will run at idle is around 13.5. If you want to lean it further be sure your acc pumps have no play in them so they come in immediately and also try a pump cam with more initial ramp. And timing also plays a big part in idle quality. I would lock the advance out. Most larger cams like 18+ Initial to idle clean.

 

[pl235c]

Floats are spot on (IMO, but that aint saying much) with the sight screw removed fuel just barely trickles out the hole,
I set the arms on the accelerator pumps with a feeler guage at .015 if I remember correctly, I think its idling at about a 1:1 AF ratio, lol.

if the power valve is held shut with vacuum wont it stay open if there isnt enough vacuum to hold it shut?

I'm going to try a 2.5 pv and see if that helps I'll keep you guys posted

the advance is plugged so it should'nt be moving

 

[SSmonte408]

if the power valve is held shut with vacuum wont it stay open if there isnt enough vacuum to hold it shut?

yup.

 

[slimbo]

if the power valve is held shut with vacuum wont it stay open if there isnt enough vacuum to hold it shut?

yup.

it can stay open all it wants.....its not going to add fuel until the boosters start to flow. the power valve being open adds NO fuel at idle....

 

[holtjohn]

then how come when one is blown it will, there isnt a circuit it leaks into?

 

[slimbo]

when the diaphram tears it allows fuel into a totally seperate area than the valve actually flows to.

 

[Anonymous]

do you have power brakes on your car? my booster went bad and i had the same issue with holding the rpm up until the vacuum stabilized. :-k

 

[pl235c]

manual brakes, yesterday I changed the powervalve and put a vacuum guage on it and reset the carb most vacuum I could get it to pull was about 7". It will idle in neutral at about 1100 and about 1000 in gear before it would drop about 300 rpm when I put it in gear, runs great, just runs rich at idle I think a better ignition would help but man it sure burns a lot of fuel when its idling.

to properly set the carb I just use a vacuum guage and adjust the mixture screws until I achieve most vacuum correct?

slimbo I understand what you mean now (I think) the power valve is basically another jet, right?