HACKGT350

i have an 84 5.0 carburated and im running very rich. everytime i go to adjust the carb to make it lean it messes with my idle really bad. it makes it pulse between 1000 and 700 rpms anyone have any ideas? im getting like 6 miles to the gallon right now im down half a tank for tuesday and its only been about 53 miles.

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ZachW04Stang

There isn't an idle adjustment screw? I though holleys had those?

HACKGT350

yeah i can adjust the idle but to get it to stop pulsing it has to be up over 1000 rpm's and i dont like it that high

Mallonpaulj

Not sure what you may have tried but I have seen the floats in Ford Carbs soak up fuel (hard black plastic ones) or develop a leak and fille with fuel (metal ones) Either way, the float does not 'float' correctly and allows excessive fuel level.

Leaning out the idle screws won't help because its more in the main metering circuits. Pull the top of the car off and just check the floats. I had one that literally had burned the toe off the float from a minor backfire and carb fire. New float was all it took.

HACKGT350

thing is its a brand new carb i bought it in october and its been like that since i put it on even the old one was the same way car was running increadibly rich

Ecstasy

dont feel bad man, my gas mileage is screwed a little too i believe, when i start my car up or rev it up i smell fuel.

My85QuarterHorse

If thats an out of the box Carb, and its a 650 double pumper....on what looks like basically a stock car with some exhaust mods, it needs jetted down. The stock application on that car was a 500. I don't know what size jets a 650 comes with...you'll have to look at them they will be marked. It sounds like its running EXTREMELY rich if you are only getting 6 miles to the gallon, so id start by dropping 2 on the primaries and secondaries. Drive the car for a day or so...see how its acting. Get into 3rd gear...hold the car at about 3000 RPM's for about a half mile, if the car is loping...you can feel it surge now and then..its loading up a bit and needs to lean out a little more, go down a size on the primaries....take it for a spin again.

Run down to pep boys or auto zone and grab a couple jet kits...you should be able to get 90-100, and 80-90 for 15 bucks a set. The jet kits will be handy later on, because as you make mods (Heads, cam, Intake) you'll need to rich it back up. Might as well grab a couple bowl gaskets while you are there....unless you get lucky you are going to be pulling the bowls off and putting them on a few times, might get one leaking or somthing, normally you won't need the gaskets, but they are cheap enough and handy to have around.

Save yourself a little time and only change the primaries at first...get those right. ONce you get the primaries right...go 2 under on the secondaries. That way you are only pulling one bowl.

Do yourself another favor, while you are at the auto partsstore...buy a book on tuning holley carbs, after you change the jets you are going to have to do some tuning on the carb. And you can turn screws forever and never get it right. Holleys are NICE once you get them set....its the getting them set part that sucks!!!

Good luck!!

tokinGLX

the stock carb was actually a 600 cfm holley. holleys jet kit is part number 36-181, it has 2 jets of every size from 64 to 99. i bought a 4777-7 and it was jetted a bit rich. something else you may want to check into is teflon taping almost all the things you can, you might have a slight leak. does it smell like gasoline when you are driving¿ those were the problems i had with mine out of the box, now its much better

HACKGT350

yeah it does smell a little like gas but not bad and thanks for all the help ill head to my speed shop when i get my next pay check haha i put all my money into gas on that car haha im at the pump like 3 times a week

My85QuarterHorse

I stand corrected, the stock application was a 600, not sure why I thought it was a 500.

I bought an Edelbrock 600 carb myself, My car has had some mild head work done...but the carb was still a little rich from the box. I think the stock jets were 102 primaries, and 98 secondaries.