Acceleration
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Acceleration
I bought a 1973 F100 yesterday. Automatic. Lots of new parts. Cranks great and idles fine at first. After driving for a few miles when I attempt to accelerate she starts to sputter as if it's not getting gas or opening up. The only thing I know for sure that needs fixing is the manual choke. Suggestions? Thanks!
Lead Driver
Joined: Jul 2017
Posts: 9,601
Likes: 1,174
From: San Jose, CA
Is the choke not working at all, or does it stay closed longer than it should? If the latter, then that could cause your issue. But if it's always open, then it's probably something else unless the problem goes away later when it's super warm?
Is your vacuum advance connected to anything? Often they are controlled by thermally activated switches/valves mounted in the intake area so that there is vacuum only after reaching a certain temperature. Maybe if yours has one or more, some of them are leaking and you're getting a vacuum leak, or perhaps too much or not enough ignition advance.
Do you have tune-up tools? A timing light would tell you a lot right now about the spark and how things are working. Like the mechanical advance too.
It's not that this issue has to be caused by an ignition problem, but that's a place to start. It could also be a fuel starvation issue, but start with some basics no matter what.
What parts are new? Has it had a tune-up in awhile? Is it running an old points ignition, or has it been upgraded to electronic?
Good luck. And welcome to FTE too!
Paul
Is your vacuum advance connected to anything? Often they are controlled by thermally activated switches/valves mounted in the intake area so that there is vacuum only after reaching a certain temperature. Maybe if yours has one or more, some of them are leaking and you're getting a vacuum leak, or perhaps too much or not enough ignition advance.
Do you have tune-up tools? A timing light would tell you a lot right now about the spark and how things are working. Like the mechanical advance too.
It's not that this issue has to be caused by an ignition problem, but that's a place to start. It could also be a fuel starvation issue, but start with some basics no matter what.
What parts are new? Has it had a tune-up in awhile? Is it running an old points ignition, or has it been upgraded to electronic?
Good luck. And welcome to FTE too!
Paul
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Fleet Mechanic
Joined: Sep 2014
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From: NE Texas
while you are getting the basic stuff together, make sure you pick up some carb cleaner.. besides helping knock some of the carp off, it is a good diagnostic for a vacuum leak - while the engine is running, anyplace you have a vacuum leak will suck the carb cleaner into the engine and it will change how it is running. Helps narrow down leaks. Not necessarily a cure-all but it never hurts to have a cleaner engine, too.
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