HI there

I've had such a problem with this truck.
I bought it from my great grandpa.....with only 103,00 miles on this 78 300,6cyl. I replaced the manifolds. because old ones were cracked.....the truck has always had a problem with needing to be primed after just a few days cause the gas leaks back into tank. Its been rebuilt in the 80s, (carb) and i recently rebuilt the carb.....and i can get it to run...but not very good...here are the sypmtoms....it starts right up cold( i dont havethe air cleaner on or heat vent) then it will run just fine for as long as you let it sits (longest let it sit is about 20 min.) then i put it in drive and the truck was on about 4000 rpm then as soon as its in drive it bogs down.....and bout after i get 400 feet it kills....and will start again. to go another 200 feet. and if i put it back in park it gos back to high idle again and within 5 minutes it died... i am having troubles adjusting the fast idle, and i dont knwo what else could be the matter.....COULD SOMEONE PLEASE HELP ME i NEED A REPLY BY TOMMOROW 130PM i have know clue whats going on....it has about 16 vacum pressure.......you can email me at Grinder619@aol.com any more questions about symptoms i can answer............im thinking about buying a performance two barrel compared to my one barrel now..... PLEASE HELP ~thank you -Paul

 

Change the fuel filter & check the fuel pump pressure.

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Fuel line or intake manifold leaking? Fuel pump maybe? mil1ion is right though, check easy first. I would fix the problems with the carb and setup that you have right now instead of throwing parts at it.

 

Stuck choke.

 

I dont think there is a intake manifold leak......because i had one already......and the vacum pressure is stable.... at 16 vacum psi........im so confused about this....i need help....i would hate to bring it to a mechanic i am kind of tight on money. i dont knwo how to check fuel pump pressure....still need help

 

Same tool you checked the vacuum with Usually

 

How do i get that choke to get unstuck.........would it bog down if it got to hot.....temp wise. i dont have a functioning temp guage.???

 

Work the choke blade back and forth and spray it with some carb cleaner or light solvent or lubricant like WD-40 will help.

 

personally i dont think the choke is stuck cause i can move it with my hand freely..............

 

could the jets in the carb be clogged? more vacume sucking gas in with the choke on, then no flow when the choke comes open? I think those carbs used a metering rod and not the jets we are used to.

More a question then a suggestion, I don't know - but I would dismantal the carb next.

 

carb rebuild may not be a bad thought, I would still check the fuel filter and pump as well. Is the carb gummed up on the top end at all? (Thinking along the lines of the clogged jets or metering rod)

EDIT:

electric choke? check the wires and ensure power to choke.
vacuum choke? check hose to choke

Trying to think of anything creative.

 

How long has this truck sat without being started,before you got it ?

 

OOPS, he said he had rebuilt the carb - could it just be out of adjustment?

 

how about a plugged fuel line? same symtoms on my houseboat. the mechanic came and did a tune up and changed the fuel filter and it still did the same thing. i took an air compressor and disconnected it from everything and i blew the air threw the line and it blew out a chunk of crap. now runs like new. hope this helps.

1978 F-250 Ranger Explorer 4x4


Drive It Like You Stole It!!!

 

Yah i rebuilt the carb......could it just be out of adjustment for the high idle(choke idle)????? or choke....Like i said It runs and starts when cold then when it gets warm or i put it in gear it bogs down.....and dies shortly...... dont knwo how to explain better?