I just bought a 1986 f-150 with the 351 engine. Only 77k miles, great shape.
The engine runs and starts fine. But when it's cold (hasn't been run all night), after starting when I try to put it in gear (automatic) it stalls.
I have to let it run for 10 minutes or so before it will keep running after I put it in gear.
Once the engine has been run it starts and goes every time.
I checked the choke to see if it was sticking, it seems fine. Sprayed it and the carb. out with cleaner.
Thanks for any help.

 

That does sound like the choke isnt far enough set or its not working at all. Is it electric or manual? Is the plate wide open or part or all the way closed when cold? Have you checked the timing? when its cold the combustion process is much more difficult. when its hot the fuel is vaporized so it explodes much easier.


Welcome to FTE!

 

I've only had the truck a week. I really like it. It's going to be getting cold here soon (western NY) so I'm worried about this problem.
I believe it's a manual choke, but I'm not positive. I haven't had time to check much with the truck.
I'm new to anything with a carb. so I wasn't sure where to start looking.
I will try to check the timing though.
It does run really nice, it's just that stalling problem when cold.
Thanks for the input.

 

Its getting cold here to so i just figured out why mine was stalling to! it was the choke.

 

I doesn't have a manual choke unless someone has changed it. Look on the passenger side of the carburetor near the top for a black disk that looks like a 2" diameter hockey puck. That is the choke thermostat. Grab it and see if it's loose. You shouldn't be able to spin it without loosening its attaching screws. If it's loose, that's your problem. If it's not you need to adjust it. I'll get to that later.

Is there a metal tube going to and from the passenger side exhaust manifold? Does it appear to be in good shape? This is the hot air supply used to open the choke and you really need it for the choke to work.

Unplug the wire from the themostat, take the three screws out and remove the retaining ring and gently remove the choke thermostat. Make sure there is a gasket between the thermostat cap and body. Make sure the choke plate opens and closes smoothly and easily moving the forked tab exposed when you removed the cap. Reinstal the cap making sure the end of the spring is captured in the fork of the tab but don't tighten the screws just yet. Hold the throttle open with one hand (or have a helper hold the gas pedal down) and turn the thermostat enough to close the choke while the engine is cold. Tighten the screws and plug in the wire.

Start the engine. The choke pulldown diaphragm to the rear of the thermostat should immediately open the choke a little bit and the engine should be idling at a good clip (maybe 1800 rpm). The choke should open slowly and be fully open within 3 - 5 minutes. After about a minute you should be able to bump the throttle and drop back to a more normal idle speed.

 

My 86 f150 use to do the same thing, also a automatic with the 351.

I bought a "HELP!" brand manual choke kit for like 10 bucks at carquest. A manual choke is a pull cable that manually lets you operate the choke by hand from inside the cab. It starts so much easier with the manual choke, just yank it out start the truck and push the choke about half way in, I don't even have to pump the gas.

The good part about the manual choke is you can put it in gear and run it down the road with the choke still on. I installed the kit last winter, I'd come out in the morning start the truck and take off, she'd idle about 20 mph down the road with the choke on, but by the time I was at the end of my street the engine was warm.

Also if I pull up to stop light when its cold and she starts sputtering I just pull the choke a little to keep her alive until the engine is warm.

I took possession of both my old trucks when they were 20+ years old, neither had a functioning choke. Instead of dealing with all the factory choke related crap I just installed something that I could depend on.