tomster03

Ok maybe some one could help here. Imnot an expert on carbs i just know the basics and how to tune them in... But see ive had this Holly for a little wile now "650" and i will tune it in perfict for my car one day while the car is warm. then i'll go out there the next day and it will hessatate BAD!! and if i really tromp on it it will fall on its face and i have to retune it but it seems like a weekly thing... the car really dont get drove much but this is just anoying!!!

tomster03

I forgot to put that when it does that hesatating bull crap it falls it pops out the carb some ............HELP Me Out here guys! Im about to pitch that dang carb and go with a eldbrock

Jester

You're not supposed to really tromp on your car when it's cold

Seriously..does it do it when warm or only when cold?

Poping through the carb when you give it gas liek that is a sign of a lean pump shot. Either because of an internal leak/blockage, being tuned badly, or someone trouncing in it when cold with no/badly adjusted choke.

JRoy91RS

Who's Holly, and where can I meet her? just kidding. You may have a blown power valve, also. I would check that out. You don't have to go edelbrock.

tomster03

Nope this is after its worm... i just dont get how one day its fine and the next its not at the same temps about 210

IHI

iTrader: (1)

My buddy has a 700MS and was having the same problem, checked floats-O.K., checked ignition-O.K., made sure we had correct power valve and that it was still intact, found out that there was too much slop between accelerator pump arm, set it to Holley's recommended .015 and now it's cured. When I put my new 750VS on last Friday I noticed that it was tight-no gap what-so-ever, I figured they must be different from MS to VS cause believe it or not I bolted it on, floats were right on, and idle mixture screws were real close, runs like a champ even though see's lean. All I have to do now is play with jets after I put adjustable secondaries on.

tomster03

OK i need to know how would the car act with a blown power vaulve? would it have the semtoms that mine has.. it is fouling out cylinders too... HELP please

IHI

iTrader: (1)

That popping is one syptom of a blown power valve, just for my own curiosity, is this a carb you bought new and installed from day one, or one you got from a buddy and put on? If you've always had it, did it have these syptoms before or did they just pop up outta the blue. Was the carb recently rebuit by any one? The reason I ask cause my friend went through 3 Holleys and 1
Edelbrock (used of coarse) the car ran but not worth a **** so he sprung for the new 700-WHAT A DIFFERENCE! I don't think in my area there's anybody that knows how to rebuild a carb cause I've never seen one work right after a rebuild, but that's just my experience.

tomster03

i rebiult my motor and it was after that i put it on and had it pop a couple times from timming off set that and it ran good for a little wile then it started acting up Big time. it is flooding out my car and really SUCKS...

IHI

iTrader: (1)

If timing was off and then it was popping through the carb, it might very well be a bad power valve. When these valves go bad and get a hole in the diaphram they allow excess fuel through which would explain your extremely rich condition. You can check it yourself by taking it out and cleaning thouroughly, then stick it between your lips and blow, if it lets air go through or if you suck on it and it won't hold a vaccum, then there's a hole in the diaphram somewhere. You could also let the wife/girlfreind do this for good practice Try that first and rule it out, hell they're only like $8 I think.

88Bravo

But for a couple of dollars more you can get a power valve replacer. All it does is take out the power valve and plug the hole. $8 isn't bad, but how offten do you want to spend the money??

IHI

iTrader: (1)

The power valve richens the mixture under heavy loads and acceleration. If you plug the power valve, you'll have to increase the main jets to proper size for crusing (if that the cars sole purpose, but then if you do any in town driving be prepared to foul plugs BIG TIME, since you increased the main jets to compensate for not having a power valve ALL the fuel is going to be straight dumped into the cylinders-which you had previously set for cruising rpm. Plugging power valve on street/strip, daily driver is bad, bad, bad idea. Get the power valve protector if your concerned, Summit and Jegs both sell them.