Hi, I'm new to forum but have been reading lots lately. I have just started working on a 1978 F-150 Ranger with 90,371 miles on it...351/400 and I think I can read a c6 tranny. Hasn't been ran much during the last few years but is in OK shape except for a little rust and the worst thing....me trying to work on it. It will be a wonderful project for me and my sons to work on together.

Truck ran ok when I got it but I screwed it up. We put 5 galons of 87 octane gas in along with a small bit of Redline fuel system cleaner. Gas also might have had a small bit of Stabil it it as well ( somewhat fresh gas used for lawn tractor... gas no more than three weeks old at most ).

After cooling system back flush, oil/filter change, transmission fluid change, power steering fluid change, new fuel filter and new air filter I was ready to test. Before installing more new parts..belts, hoses, plugs, I wanted to check truck status. Motor would not idle at all...or not more than a few seconds. Before I started with it it idled for about 10 to 15 minutes before cutting off. No it will only run a few seconds unless I hold carb open or gas pedal down.

I tried cleaning carb...used almost half can of spray with no results...other than a cleaner carb I did not clean inside of carb with throttle body brush, only carb/injector spray.

What did I srew up? Where do I go from here?

I am buying timing light and maybe vacume system test unit?

Any help would be appreciated.....

Thanks in advance

Charles

 

Sounds like a float issue in the carb, to me.

 

What caused a float problem...my adding gas?? Bad gas?? or cleaning the carb??

 

Looks like you have experiance with 351m's. Thanks for the help.

What caused float to stick? Ran OK before I started working on it. Could I have stirred up crap in gas tank? Added bad gas?

Thanks

 

like he said it could be the float. u may have trash in the carb now. When they sit for a while the rust settles to the bottom. I've let mine sit b4 and that happened. I would sugguest u taking the lines off at the tank and at the fuel pump and taking a compressor and blowing the fuel line out. And if it has the original factory gas tank in it i would also sugguest getting a new one. Therefore it'll be clean with no rust.

 

Could've stirred up crap in the tank or the bowl. Could be a bad float. That'd be the first things I would look at.

It may just be a coincidence that it started acting up now.

 

Find your fuel filter and replace it! If it's got an external fuel filter (hopefully) then replace that turkey. Otherwise, I'd pull the inlet off the carb and check for crud.

 

thanks guys,

I changed the fuel filter that connects to the carb. Is there another one at the gas tank??... the exteral one?? Are there any fuel screens?? Sorry for the questions but I haven't found a manual for it yet.

The truck has sat lots during its life..averaged only 3100 miles per year and hardly none the past three or four years. Has a little over 90k miles on it.

I will clean the fuel line. Could I try cleaning the fuel tank with a boat sump pump?? I will look at a new tank as well but wasn't planning that for a while.

The float might be a problem as I have never gone into a carb...any suggestions on a guide for rebuilding carb?

thanks for the help

 

If the truck has been sitting for that long, I would check the vacum lines for dry rot.

 

Wow, can't find problem. Float looks good, clean and moving freely. Carb could use a rebuild as gaskets are old but still OK. Vacum lines look good and most even look new....maybe they have been replaced.

Two thing seem wrong though. When I press gas pedal I only see one spray of fuel from carb jet. The fuel that comes from the bowl behind float into carb looks like it is coming from drivers side only?? Should there be a stream for each bank of the carb?? Is a jet clogged??

Also, there is a small black cylinder on the drivers side that has a smaller button on top. Looks to guide or regulate the travel on the gas pedal linkage. This device has a plug on it that is not pluged to anything...looks like maybe the problem??

Where does this ghost plug go??

 

Pictures help to identify objects.

A service manual will have many pictures in it.

A choke that does not open will also cause the engine to die.

 

well your ghost plug cylinder thing( not sure what its called) it does help a little, if you connect it to the wire harness by the cowling, it should plug right into the plug in the harness unless someone cut it off. Any way what it does is gives it a little gas so that it gets warmer faster I think, also check your choke like you said. I bought my truck 2 years ago now and gained some knowledge about it. Im only 17 so dont hold me to anything,but my truck had one but the wire ripped out and I dont use it so i threw it out. Any way rebuild the carb and clean it good sence its not new, carb kits are cheap and have a diagram with them to show you what to do. dont go buy a reman carb i did it and it was junk, came from autozone. Im happy to help you, if you got pics show me them and i could point somethings out.

 

The cylinder sounds like the cruise control module...

Do you have a 2v or 4v carb? 2v would be a Motorcraft 2150, these are very easy to rebuild, even for a novice, kits are $15-$35 depending on the tag. Be sure to take the info on that tag to the parts store for the correct kit. The kit will likely contain multiple applications but only one set of gaskets will fit.

 

Thanks for the help, my sons and I are getting a lot out of this.. there is nothing better than working thru issues to solve a problem.

Store has to find rebuild kit for my model carb. That should help things.

I just found out that the black cylinder that I was refering to in my other post ( ..see.. carb, fuel section ) is maybe an electric choke....I thought they were operated by the vacum systerm. This cylinder is not plugged in to anything...and even worse there is nothing anywhere close to plug it into??

Also, truck idles fine during the first few minutes after start up but then seems to want to cut out after warming up. Just found out no thermostat in truck. I will install one when I finish the extensive coolant system flush.

Oh well, still waiting to locate manual for 78 Ford. I guess I need to just order online.

Thanks

 

The electric choke assist hooks into the stator terminal on the voltage regulator. The choke is also operated by heated air from the exhaust crossover in the manifold. Two tubes enter and exit the carb for the heated air supply. There are pictures in the service manual.