Hard start hot

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Feb 28, 2017 | 06:11 PM

swmr1

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Hard start hot

I have a 1983 f150 with a 4.9l straight 6. It starts great when cold. After driving for 15 min or more and turn it off it has issues starting up again. It cranks just fine. And to get it to actually start i have to crank for 15 seconds with the throttle wide open and at that point it starts to slowly fire and finally gets going.

What could be the cause of this and what could fix this?

Feb 28, 2017 | 10:17 PM

Brnfree

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I don't know anything about your set up but off hand I'd check the choke. Check and see if it's opening (at full operating temperature) and that its not bound up with crud. If they're dirty clean the springs with some carb cleaner and follow up with a little oil on the springs and pivot points.

Otherwise, maybe don't touch the gas when you try to re-start it. That's usually my best bet for a warm engine that hasn't sat too long. Touching the gas allows the choke to close back up resulting in a rich restart.

Mar 1, 2017 | 08:46 AM

Franklin2

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From: Virginia

When you turn it off after it gets hot, go take the aircleaner off and look down the carb throat with a flashlight. If you see fuel dripping into the engine that is a problem. Most likely your fuel level is too high in the bowl and I would put a kit in the carb.

Mar 1, 2017 | 08:59 AM

1986F150six

Lead Driver

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From: Sheffield, AL

Due to having the exhaust manifold directly under the carburetor [six cylinder], heat can boil the fuel in the incoming fuel line or float bowl. Some have had success insulating the fuel line or placing a phenolic spacer under the carburetor.

Mar 2, 2017 | 12:16 AM

swmr1

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To give a little more background I have a holly 4 barrel with offenhouser dp intake and a 1 inch aluminum spacer and EFI exhaust manifolds.

I have not gotten the chance yet to check the dripping of fuel.

Mar 2, 2017 | 05:57 AM

Franklin2

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From: Virginia

If you have a Holley 4 barrel, put a rag around the carb and pull the site plugs. If fuel runs out, it's too high. You can pull the needle assembly completely out on most Holley's, clean any dirt out, oil the o-ring, and put it back in and adjust the height, all without pulling the carb off or apart.

Aug 2, 2018 | 04:40 PM

TeeCee1968

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Joined: Aug 2018

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HOT START SOLVED

Quote:

Originally Posted by swmr1

I drive a 1968 Ford F100, I was having same issue with my truck here is what I did and problems solved.
1. Changed the COOLANT TEMPERATURE SENSOR
2. Changed thermostat fom180% to 195%
3. Made and installed heat shield out of aluminum pie pan
PROBLEM SOLVED!