I'm getting to my wits end on this, and hope someone knows what is going on here. Here goes.... Wifes 1st car she bought in 1994. 1973 Comet 250 cu in. Very stock. Great condition for 96,000 miles. California car. (Not sure if they were different for CA) Ran pretty good, then parked over a year ago. When we started it again the fuel pump gushed fuel. Replaced fuel pump. It would start but barely ran. Did the plugs, Dist cap and rotor, points, condenser, coil, and timing, new gas, fuel filter(cut open old filter, is clean). Now, it starts great, and idles great for about 30 seconds...then runs rough, getting so rough that it will stall. BUT,...It runs very good if I give it gas and keep the revs up. If I step on it, it revs right up, and drives around fine unless I coast at near idle, or idle at a stop sign...then runs real rough and I gotta gas it quick to keep it running, pretty much makes it undriveable, it will stall There is some gas that seeps out around the fiber carb/manifold gasket onto the "heat shield" also gas pools up on top of the float bowl where the rod comes out of the top of the float bowl. I took the carb off and the bowl was pretty clean. No obvious fuel in the float, idle jet was spotless. the float valve little rubber pointy end "looked" perfect. I blew out what I could...also there was a pool of gas inside the intake manifold. Could it be the new fuel pump has too much pressure? There is no sealent at the Carb/manifold joint-should there be? Maybe a vacuum leak is happening? Where do you check vacuum? The choke does start to open. I've tried opening and closing the choke by hand...no difference. Im in Oakland CA and getting the carb rebuilt professionally here is not that easy. And the carb looks so clean anyways, Im almost afraid to have someone mess with it. Anyways sorry for the long story. Sure would like some thoughts on this. Thanks
I would say it's a bad needle/seat or a leaking float. It's hard to tell by looking weather the viton tip is bad or not.
Yesterday I get the car to start and run awesome! I took the fuel tank, lines and pump out of the equation. Ran 5/16 tubing with a funnel to the fuel filter at the carb. Engine purred like a kitten, just ran great. So I think the NEW part is the problem, or the float needle. New pump is producing too much pressure for the float valve, and was flooding the carb. I'm going to change out the float needle just in case it's not sealing, because any fuel pump will produce more pressure than the gravity feed I was testing with. Also I'm getting an inline fuel pressure regulator. Glad its not the float. They are like 60-70 bucks now. Thanks for the reply Mavrocket. Oh, I did notice water in the little bit of fuel that was pumped out of the fuel pump. So I should clean the fuel tank too.
If you are using the factory style mechanical fuel pump, I seriously doubt it is producing too much pressure. I think Bob is probably spot on with the needle & seat and/or float. Rebuild the carb, especially if it has sat around with gas in it for a year or more.
I had a similar issue in my Mustang and yes, overhauling the carb help tremandously as float was, well not floating much anymore! Do you have an electronic ignition? If it sat for a year and you're replacing / checking / changing a few things, it's worth it to also install one, starts and runs smoother wiht one
I installed a Mr. Gasket fuel pressure regulator to reduce the fuel pressure, and that is working great....for now. I've read that the Mr. Gasket regulator work great for some. but fail quick for others. I did order a new float valve needle and seat just for good measure. Runs and drives awesome! Now to tackle the radio speaker, instrument cluster lights, and maybe the squeaky front suspension. Thanks for replies and help.
