Holly issues

[Caminojr85]

ok so i have a SBC 355 mild cam, proformer intake, headers, nothing too fancy or wild. so the issue im having, huge amount of flooding/low RPM issues. its an electric choke 600 cfm Vac secondarys, when the motor is cool (160) or less there is no real issues, the warmer it gets it acts up more, basicly loading up/wont idle/ultra rich, since i work on mine alone its tough to keep it running to see whats going on, what do you all think, bad choke or fuel level too high?

[quicksilver]

Sounds like a fuel level problem to me. With tke car shut off and on level ground take out the sight level caps and if fuel runs out it is to high or maby a little trash under a needle valve. I adjust my fuel level to where if you shake the car just a little some will splash out.

[NotoriousGreaseMonkey]

Its the power valve, its always the power valve.. LOL.. Seriously check the power valve.

[cefolar]

Sounds like a fuel level problem to me. With tke car shut off and on level ground take out the sight level caps and if fuel runs out it is to high or maby a little trash under a needle valve. I adjust my fuel level to where if you shake the car just a little some will splash out.

+1 - sounds like a float level to me.

[SATAN]

I would check the float level first since it's easy to do, then I'd replace the power valve.

[Caminojr85]

thanks all ill jump on the floats, if its the power valve im returning this carb and buying a diffrent one, this is the 2nd holly to give me a hard time in less then 100 miles on the motor, first blew 2 gaskets and was pouring gas all over the motor, now this one... -.-;; but yes i was thinking float checks, sounds like a duck quacks like a duck...ect... thanks for the opinions, ill let you all know

[Chuck M]

Clean your "needle and seats" real well also, Do you have an electric fuel pump? You might need a regulator for the pump!

[Caminojr85]

figured it out, it was a float level...but it was due to too much fuel pressure, so it blew the floats out lol, i figured a holly carb would handle a standard mechanical fuel pump but that carb can only take 3-6lbs of pressure, mine is 7.5-9ish so...im dumping that old carb back to holly and buying the new 4150 650 dbl pumper ultra >:)

[cefolar]

Any Holley carb should be able to handle anywhere from 6-9lbs of pressure. Changing to a 4150 won't help handle your fuel pressure issue, you should still regulate it down to about 7lbs. What fuel pump are you running? Most aftermarket mechanical fuel pumps are self regulated to 6-7lbs. unless you have what is defined as a "high flow" mechanical pump. So, if it were me, I wouldn't bank on the pressure being the issue - but swpping to a new carb will probably have the correct float adjustment and solve the problem anyway.

[kevinr]

I run 9lbs on the dyno on all kinds of Holley carbs all the time,never blow the seats off, pull the float make sure its not saturated (if nytril) or has fuel in it (if brass) causes them to ride a little low and tend to be a little lazy, and power valves can be iritating

[Caminojr85]

ok ill be more clear lol, the carb i had was a 600 cfm Rebuilt by holly Vac secondary cheapo carb, has a holly name and holly parts but its a peice of junk, the fuel pressure rating on it is only 3-6 Lbs. Per holly, i have a H.O. Fuel pump for a 1971 chevrolet nova that puts in the 7-9 range, so im assuming it was/is overpower the floats and letting raw fuel into the motor once the motor warms up and fuel pressure begins to build/back log, thats why it'll run fine going down the road but a quick step off the pedal and it will idle poorly/try to die, so to fix it, since the carb doesnt have Adjustable Floats <--- not kidding, i put a fuel pressure regulator on it and an accurate fuel pressure guage reading 4.5-5lbs, and now the carb will not retain an idle whats so ever, so im assuming there is something wrong with the carb, and even if there isnt, it is under warranty and im going to return it for the simple fact it has very few adjustable features, i'm upgrading to a holly 650 ultra DP with electric choke, its light weight, has 4 corner idle adjustments and clear bowl plugs already installed, not to mention, its awful pretty :) i also order a Holly dual fuel log with jegs fuel pressure guage, and a holly Max 4.5-9psi fuel pressure reg. now im not writing all this out to sound like a jerk, i just typed the other posts before i had thought much and with less then stellar info on the carb i had, but its all gonna be fixed in about a week when my new fuel system comes in :) Thanks all for a help, im sure ill need more when it comes to fine tuning that carb, but lets see what happens

[kevinr]

try this before u change carbs, just to see if it works, i would still change carbs anyway you will be happier, take a blow gun at the front and rear float bowl vents and blow them clean, sometimes fuel will get caught in them and cause the press. to increase in the fuelbowl creating a positive presure pushing more fuel thru the jets (rich mixture) just a thought!!

[Caminojr85]

that is a good idea, i can see that, basicly creating more of an "atmosphere" of weight pressure on top of the fuel...ill give it a shot if i have time tomorrow lol, going on vacation thurs. :D