Engine won't shut off
New User
Joined: Dec 2002
Posts: 9
Likes: 0
Engine won't shut off
Hello Everyone
Recently I purchased a '73 F100 long bed.
I'm having trouble w/ the engine--it won't shut off at times.
In other words, some times when I come to a halt and turn the engine off it turns off fine, other times the engine jumps and sputters and eventually gasps before it turns off.
what I've done:
1. Checked the timing: twice already. I'm having difficulty making sure the distributor is tightly screwed on since there is an aftermarket compressor adjacent to it that keeps me from fully tightening the screw that holds the distributor to the engine. Still, I believe I am eventually able to tighten it well.
2. Checked the RPMs and adjusted these at about 700RPMs on the carburetor. This is an aftermarket carburetor, an Edelbrock. Don't know the specs on it aside from the fact that it is a 4 barrel. The intake manifold is also an Edelbrock--perhaps this might have something to do w/ it.
What are your suggestions?
Thanks.
Recently I purchased a '73 F100 long bed.
I'm having trouble w/ the engine--it won't shut off at times.
In other words, some times when I come to a halt and turn the engine off it turns off fine, other times the engine jumps and sputters and eventually gasps before it turns off.
what I've done:
1. Checked the timing: twice already. I'm having difficulty making sure the distributor is tightly screwed on since there is an aftermarket compressor adjacent to it that keeps me from fully tightening the screw that holds the distributor to the engine. Still, I believe I am eventually able to tighten it well.
2. Checked the RPMs and adjusted these at about 700RPMs on the carburetor. This is an aftermarket carburetor, an Edelbrock. Don't know the specs on it aside from the fact that it is a 4 barrel. The intake manifold is also an Edelbrock--perhaps this might have something to do w/ it.
What are your suggestions?
Thanks.
More Turbo
Joined: Aug 2000
Posts: 721
Likes: 1
From: Floyd, Va
Engine won't shut off
What do your plugs look like? Brown? White? Oily? Are they the correct ones?
Please dont be insulted by this. Your lack of shutdown is due to a heat source present when it shouldnt be.
1. You checked your timing, so we can probly check that one off.
2. I have heard of the incorrect temp pluggs causing problems like this.
3. If these are ok, i would default back to the timing. Try timing by vaccuum instead of the timing mark. Some engines just wont run correctly at the mark. Mixmatched parts can do this sometimes. If you dont have a vaccuum guage, try just backing off your timing a degree or two and see if that helps. If not, maybe someone else can come up with something else to try.
Good luck
Tony Warren
Nebraska
Please dont be insulted by this. Your lack of shutdown is due to a heat source present when it shouldnt be.
1. You checked your timing, so we can probly check that one off.
2. I have heard of the incorrect temp pluggs causing problems like this.
3. If these are ok, i would default back to the timing. Try timing by vaccuum instead of the timing mark. Some engines just wont run correctly at the mark. Mixmatched parts can do this sometimes. If you dont have a vaccuum guage, try just backing off your timing a degree or two and see if that helps. If not, maybe someone else can come up with something else to try.
Good luck
Tony Warren
Nebraska
Moderator
Joined: Jan 2001
Posts: 56,971
Likes: 2,730
From: Virginia
Engine won't shut off
Restricting the air intake to the engine will cure your problems too. You have been looking at the idle speed, and that is a good place to start. Will it run ok at a lower idle rpm? Say 500 rpm. if it will, this may be enough to cure the problem. Alot of the factory set-ups used a solenoid that held the throttle at idle rpm, and dropped back when you turned the key off to completely close the carb to prevent dieseling(the official term for your problem). You must have a hot spot in the combustion chambers, either carbon that is glowing red, or something. When you turn the key off, there is enough airflow through the carb to keep adding fuel, and whatever is glowing red is igniting the fuel, even though the sparkplugs are not firing, making the engine continue to run.
Elder User
Joined: Aug 2002
Posts: 662
Likes: 0
From: CA
Engine won't shut off
This is commonly called 'after run' or 'run on' and 95% of the time it's due to plugs in too hot a range. They got so hot there like a glow plug, and they keep the engine running till they get too cool. As another ford guy said, it could also be a carbon chunk in a few cylinders (doesn't have to be all of them) that's doing it. bad timing can certainly contribute to it, but it's not the cause as there has to be some source of ignition causing it.
One other possibility, though it's not likely, your ignition switch might be going bad, and instead of switching completely off, it allows a little bit of current to pass through now and then, causing some spark in the plugs. This is especially true if you're running an MSD or other capacitive ignition.
One other possibility, though it's not likely, your ignition switch might be going bad, and instead of switching completely off, it allows a little bit of current to pass through now and then, causing some spark in the plugs. This is especially true if you're running an MSD or other capacitive ignition.
New User
Joined: Dec 2002
Posts: 9
Likes: 0
Engine won't shut off
Thank you.
I am new to this w/ not much experience--so no I am not insulted by your suggestions in any way. As I see it, like anything else, it's just a matter of time and application before I get better at this. Of course, the expert advice I get here certainly helps.
Jose
I am new to this w/ not much experience--so no I am not insulted by your suggestions in any way. As I see it, like anything else, it's just a matter of time and application before I get better at this. Of course, the expert advice I get here certainly helps.
Jose
Senior User
Joined: Nov 2001
Posts: 239
Likes: 0
From: West Jordan, UT
Engine won't shut off
this might be sort of late.... but do you still have the problem?
if so, does your carb have a manual or automatic choke? if you have a automatic choke, check to see if this is working. i had a similar issue, it turned out that my electric choke wasnt getting power and this was causing high idle, bad mileage and "after run". a quick fix of the electrical connection, adjusted idle and i was back in business.
if so, does your carb have a manual or automatic choke? if you have a automatic choke, check to see if this is working. i had a similar issue, it turned out that my electric choke wasnt getting power and this was causing high idle, bad mileage and "after run". a quick fix of the electrical connection, adjusted idle and i was back in business.
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