Holley Carb question
 

I installed a new Holley 650(Dbl pumper, mech sec) on my car and set the float levels and idle. I drove the car for about 30 miles that day. The car sat for a few days, then I started it, warmed it up, and went on my way. At the first 2 stops it seemed fined, but at the third stop it began to idle irratically. I nursed it back home (where it stalled). I let it sit for a few hours, started it, and noticed "drips" of gas dripping off the booster venturis into the secondaries (both barrels). I rechecked the float level and even lowered , but it still drips.

Any ideas what would cause this??????????

My friend had the same prob with his one bbl, never did find out why, we hope to know too., but after the car cooled down, it never did it again.

What fuel pressure are you running??

I don't think this is a float problem. If your'e floats were set too high, or were sticking, fuel would come up through the vent tubes. This sounds like a bad adjustment on your accelerator pumps or a bad diaphragm in the accel. pump. If the spring pressure was too high it would also force fuel out of the boosters. If the fuel pressure was too high, it could force the floats up, and again you would see it pouring out of the vent tubes. The eratic idle was due to too much fuel, and not enough demand for fuel.

Great Holley book is: "Supertuning the Holley" by Dave Emanuel, available thruogh S_A Design. Any parts house should have it.

Ron

Update ----

A buddy came over today that has more experience with carbs than I do. I started the car and let we were letting it warm up. While it was warming up it didn't drip. As it got warmer it started dripping. He didn't know what it would be either.

Fuel pressure (elec pump & reg) is set at 7 psi @ idle

I bought the book "Super Tuning & Modifying Holley Carbs", but I am hoping someone has some more pointers.

Thanks

Did you happen to check the gap setting on the accel. pumps. It sounds like with the heat something is changing...spring pressure maybe. Fuel pressure sounds fine.
Once the engine is warmed up. back off on the accel. pump adjustment screw until the boosters stop dripping, then snug her down. (it's the screw with the spring wrapped around it, one on the primary and one on the secondary)

Ron

Ron-
It has absolutely nothing to do with the accelerator pump. I think you are mistaking the squirters for the boosters. The squirters are where the fuel from the accelerator pump squirts out, and the boosters are the round items in the center of each barrel, and is where the fuel is drawn from the bowl.

GP001-
Could be a number of things:
1. Turn the idle speed down and see
if the dripping stops (1100-1200 rpm
is just starting on mainjet circuits.)
2. Idle mixture too rich; start at 1 1/2
turns out on mixture screws; warm engine,
turn idle speed down as LOW as the engine
will maintain, adjust screws (do 2 round
trips) to get highest rpm; add additional
1/8 turn out; reset idle speed to desired
rpm; shut off engine and check that both
screws are the same. If not, set both to
the average of the two. Restart engine
to check idle quality.
3. Bad power valve or leaking gasket (chk
P.V. gasket 1st, metering block gasket
2nd.)

Actually sounds like two problems: too high
of an idle speed (drips) and too rich (P.V.,
gasket, mixture adjustment) causing stalling.

Take care,
-Chris

check for a sticking needle valve..or a small piece of dirt stuck in it..are you checking the float level with the car running? idle mixture screws dont affect the boosters...the circuit for that is under the butterflies ;-)

That is correct. The mention of the mixture was to ensure that the idle mixture wasn't affecting the poor drivability. Thanks though!

Take care,
-Chris

Yep...you are right. Got the 2 mixed up. Sorry about that, I guess the "off season" is too long.

Ron

what off season? hahaha...

hey Ron.. how's the 68 comming along? ever get the headers to work?

My Holley 600 with vac secs. did this on several occasions over the years. It was always some small speck of trash in the needle and seat. Cleaning that out with carb cleaner always fixed it. Try that and see if it doesn't work.

Rev

I was having a similar problem with a vacuum secondary holley that did not have a metering block. Instead it had a metering plate. It was (I think) a 4160. When I was tightening the 5/16 bolts to put it together I was overtightening and warped the metering plate. I replaced it with a metering block from Summit, end of problem. Good luck.