sowaxeman

As the title says, I have an 85 GT with the Motorcraft/Holley 4bbl Carb. The car has 39k original miles, and is HARD AS HELL to start after its sat for a few days. It basically requires pumping the gas SEVERAL times prior to cranking, then holding the gas down while cranking. After 5-7 seconds of not firing, I repeat the process and it will finally fire, but will only run for about 3-5 seconds before the fuel is gone. Back to step one to get it to fire, then I have to hold my foot on the gas to about 2k rpms for about 10 seconds before it will stay running. So I think I have choke and fuel delivery problems from the onset. THEN after driving, when I shut it off and park it in the garage I get a pretty strong fuel smell (assuming fuel is still dumping in to the carb).

I want to pull it off this winter and do a simple re-build. Anyone got any ideas on what is causing these issues and what I should focus on for the rebuild? Are there any nice DIY write ups available on line for doing a re-build kit for the stock 4bbl on the 85's?

Please keep in mind that I am wanting this car to remain pure stock, so answers of "upgrading to EFI", or "get an Edelbrock" or some other carb won't be considered

Thanks

5IVE.OH

check your float level, make sure they are correct. Fuel filter been changed lately? It prolly wouldn't hurt to put in a rebuild kit.

pizzarolls

could just be a clogged jetting....try taking it off and blowing compressed air through any avaliable jets before rebuilding.

frdmstng1986GT

all good ideas for things too look for, here is another one. i am not sure but does the 85 motor have a electronic fuel pump or is it the old school style that bolts to the side of the block? if it is the old school style i would change it. it sounds like the fuel is draining back out of your carb wich could mean a bad fuel pump diaphram.

frdmstng1986GT

also, forgot to say that you might have a needle valve that isnt sitting correctly in it's valve and letting the car bowl drain.

tinman

1) Needle/seat problem.
2) Bad fuel pump, it's a mechanical type on the front of the engine.
3) Both in combination
I'd chance on #3.....
Insist on a genuine Holley kit by all means. What you have is really sort of a Holley 600, vac secondary. I think those kits can be had for under $30.
Get fuel pump from decent place NAPA, Car-Quest etc. Airtex is a good quality aftermarket brand for an original pump.
Those fuel pumps are not 'rebuildable' at home........

sowaxeman

Thanks guys - I'll run with that this winter when I decide to get it off the manifold and work on it.

MACDRIVE

When you flip the throttle, does the choke plate close? Get yourself a book on Holley carbs from the book store. Learn about the principles of vacuum and pressure. I find carburetors to be fasinating.

Those Holley's have an externally adjustable float level making it easy. Another thing for you to remember is Holley's are real susceptible to fuel contamination; you want to make sure you have a good filter before the inlet.

Joel5.0

^^^X2......+ check the article at http://www.flemworld.com/Hto/CMod.html

ieatpunk

I got my 85 mustang gt a couple of months ago, it has 110000 miles on it...

but i had the same exact problem, i would feather he peddle while cranking and it would finally start, only to stall again once it hit idle speed. after a few more starts it would stay running. i figured fuel filter/fuel pump. so i bought a new fuel filter first, still had the same problem. then i noticed my carb was leaking out of many places, so i bought a rebuild kit and rebuilt it. i set the floats to specification and everything...

anyways... none of that fixed the "problem"

so i was telling this to my dad and he said that he wanted to try and start it.

he started it the first try and
what he did was he pumped the gas pedal to the floor twice before starting it.

he claims he has started all of his old carbureted cars this way, but i am not sure if this is true or not.

when it starts this way it runs at about 1500 rpms for a few minutes. my dad told me that fully depressing the gas pedal engages the choke. i don't know if that is technically what happens but it works and i have no trouble starting it anymore.

but it still could be the fuel pump since i haven't replaced that yet. i have never started a mint condition 85 mustang so i don't know if this is actually how it should be started.