Cranks but won't start


Asked by Apr 24, 2016 at 03:42 PM about the 1977 Ford F-100

Question type: Maintenance & Repair

'77 Ford F100. Would run great unless you
took short trips then would have some
difficulty starting. Did notice a loss of
power about 6 months ago. Since then
have rebuilt the starter (was arcing).
Replaced the distributer cap, rotor and
coil. Fuel is  getting to carburetor (rebuilt a
year ago).
Last weekend it stalled during driving and
now won't start. Primed the carb and upon
releasing the ignition it blew the fuel out
the top. Entire exhaust system 2 years old.
Im at a loss as to what to try first. I've
heard timing chain slipped gears, clogged
exhaust, busted valve... Where should I

9 Answers


the heat riser and coil spring and butterfly choke...make sure the heat riser works....these parts flex and fail~

Kelly Mayo

take the dist cap off...look at the rotor turn endine crank pulley a couple of inches to the rotor turn with turn the engine to the right much play with the rotor till it started to go the othe way...if more that 1 inch crank rotation left and right and the rotor doeses not respond...chain/gears worn out...


Also since you would be checking out the rotor movement, just grab a hold of it and see if you can turn it. Possible that the pin holding the distributor gear in place has broken, allowing the shaft to turn, thus causing the timing to be off. Common problem and easily fixable.

Best Answer

Thank you both! Mark. That would make sense and I hadn't even thought of that. Kelly- that's a much easier way to check the timing chain without pulling it entirely apart. I was ready to tear it apart...obviously wasn't thinking clearly. I'll do both of these checks next weekend. I'm taking it up to a shop rather than working in my driveway. I'll keep you posted!

1 out of 1 people think this is helpful.

Hey everybody, Got a chance to work on it yesterday. Started with the simplest suggestion. Removed the distributer cap.... The wires that go to the "pick up coil" we're completely severed. Installed a new piece and it's running like a champ. Still doesn't explain the back pressure but at least it's running. Thank you all for your answers.


Back pressure? From where? You said you had the entire exhaust system replaced 2 years ago, I was thinking the catalytic converter may be getting plugged up, but....was that replaced?


While it wasn't running when I released the ignition it would rock back. Since it's starting now I haven't seen the same issue. I had primed the carburetor and it spot the fuel out when the ignition was released. I assume that's from back pressure.




I'd put this engine on TDC and verify that we have not jumped a tooth~

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