My 1977 302 2V Mach 1 runs and drives around fine unless I try to punch it or burn out. The motor starts to choke out, usually dies, and in order to get it started again, I have to manually open the carb and turn it over. Am I running too rich? The choke is a vac/electronic system. The electronic is wired to the solenoid and the vac is blocked off. My curb idle is about 1500rpm. which I can't get to pull down any lower, and warm is about 2000rpm. I've been told by a few parts guys to not touch the fuel/air adjustment since the factory rebuild should have already set that. Also the Vac-advance has two valves one on the front and one on top, which one goes to which vac-line on the carb?
Next on my list for now is re-replacing the fuel filter, fuel pump, fuel line, and checking the bottom of the tank. I'm not too hopeful at this point.
It injects extra fuel when you depress the throttle.
Made of butyl rubber, or a similar material, it is know to fail over time.
Feels like you are running out of fuel. If partial failure you may keep the car running by pumping the throttle pedal.
Time for a carb rebuild and that carb is one of the easiest to test your mechanical valor and patience!
BUT, you infer a rebuilt carb so that should not be the problem.
By your description of the symptoms I would point to a vacuum leak if the idle will not come down.
Also, the distributor is either not the correct one, as you have one line going to it, or someone has played with the vacuum line routing and that points once again to a leak.
Quote:
I've been told by a few parts guys to not touch the fuel/air adjustment since the factory rebuild should have already set that.
Meaning only that it should start and run. Each car is different, but this generic adjustment should not cause the major drive ability problem you describe.
Update: Fuel system from tank to filter all checked out clear as I assumed, looking into a distributor cap and rotor overhaul, I don't know if there is such a thing as overhauling the vacuum portion on the distributor though...
Also, I wasn't too be more clear, it sounds and feels like a small miss-fire at higher rpm, even when rev-ing in neutral, but it's not missing at low rpm, the putter could be just from the bogging down from whatever the issue is.
Anyone from central AZ? lol
Tominator: Thanks for the idea, the carb has a brand new rebuild from the parts store. Is it common too get a bad factory rebuild(or whatever you want to call it)? What other factors could cause it to go bad? While installing the carb, I didn't see a washer fall between the gasket and carb which resulted in a 5-8 second 6000rpm+++ run then and die. Could that have damaged the accelerator valve?
Thanks again.
If the vacuum advance on the distributer isn't working or is causing a vacuum leak it could cause a high idle and would definately bog when given gas. Are you able to slowly accelerate? If so, sound to me like a vacuum advance problem.
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97 Cobra-03 Cobra t56 and alum DS, SPEC111 clutch, FRPP 4:10,T&J Performance Forged 4v(8.9:1), Manley rods, Novi 2000 w/ Fast Track A/A I/C, Barry Grant Fuel syst., BBK longtubes and H-pipe, MSD ignition, Detroit True Track, Magnaflows, 315 NT01's on 17 x 11's, KB BAS, SCT tune and about a million other things. 575 RWHP. Going into the shop this winter, looking for 650 RWHP.
Thanks for all the help, I'm still messing with it, but something I did helped. I can now rev into higher RPM when in park or nuetral with out the bogging but I still get issues while cruising. If I don't punch it, I can run it through all the gears and get up to high speeds, but that's not the point of having a 302 now is it.
On the top of the Motorcraft Carb, there is a vac-valve on top of the bowl area. Where does this go? Block it? splice it to another line? Thanks again, I wish I new about this place four months ago.
After all this, it was more more simple than I thought. I hadn't noticed the hood insulation was torn off on one side, and at higher rmp it was robbing the engine of enough air to function accept when parked (because the hood would have been open for tuning). Thanks for all the help! Now to just fix the high idle... I will post a new thread if I need more help.
The same thing happend to my 76 Mustang Cobra. First, I replaced the fuel filter and the air filter. Then, when I was still bogging down when I burned out, I decided it was time for a carb. rebuild. Luckily, with the help of a friend, I adjusted my timing to 6 deg. BTDC (before top dead center). Then I had to readjust my carb. Since then, everythings gone smooth. Good Luck with the timing!
Possible vac. leak or the choke fast idle may be staying on
Is the choke opening all the way when the motor is warmed up?
P.S. As for timing, even with a stock 302, you can get away with more timing than the stock setting, for both increased performance and mileage. Even stock 302s vary slightly in how much ignition timing will make them run the best.
1977 Mustang 302 2V gets bogged down when floored 
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