Hey all.
I have a 73' 460. It has a Carter AFB carb. When I get up to roughly 40 to 55 Mph it loses power and won't accelerate, I would almost say it's like it's running on only half cylinders. The weird thing is that it doesn't do it every time. I drove it around and ran good small misfire and then maybe 5 hours later as soon as I get to 50 boom it runs like crap and then the next evening it runs good again. I've had the timing checked and it's dead on. I've replaced the plugs. About the plugs, the ones I took off were at .028 - .035 and they are supposed to be at .044. Put new ones in at .044. Also was looking at fuel lines and found that it does not have a fuel filter, don't know how but from the tank in the cab it runs straight to something under neath the power steering pump and then straight to the carb. One more the thing the truck is a 74 F250 original motor was a 360 if that helps.
Any help would be appreciated thanks!!!
Tyrell

 

well first thing I would do is get a fuel filter on it, you may and probably are dealing with crude in the carb. next I would pull the top off that carb and see how much is in the fuel bowls and clean them out and see if it helps

 

Ditto on filter and cleaning bowls.

Also check that the fuel level is correct and that the fuel inlet valve is clean.

Good Luck,

Jim Henderson

 

You say it runs fine when cold? First get a filter on it. then check the routing of your fuel lines,make sure there not by the exhaust system or touching the engine block( you know heat transfer). check the pump output also. (first unhook the ignition power, take the fuel line off the carb, put it in a plastic coke bottle, have some one turn the engine over, it should fill it up within 5-10 seconds of cranking)if it takes longer than that i would change the fuel pump,that thing under the power steering pump. remember to reconnect the ignition. Hope this help you RW

 

Thanks for the help, I haven't been able to even look at that thing let alone use the computer lately but as soon as I get a chance I'll get to them and let ya know thanks for the help

 

hi, go for all of the above. also check your plug gap depending on your ignition system, your .044" gap is probably too big for a factory system of the 70"s

 

Hey,

Re: this:

That makes me thing ignition wires/distributor cap.

There is an EASY test:

Take the water bottle you normally spray the g.f.'s cats with (or that she uses to spray her clothes when ironing) and spray the ignition wires, distributor AND COIL, when the engine is running, AT NIGHT.

It must be completely dark out, for this to work.

Have the g.f. rev the truck to the suspect rpm, if necessary.

What you are looking for is ARCING, visible as dim, blue-white sparks, between the wires themselves, or the wires and the engine block.

ANY arcing = Nogoodski!

Spray the Bejesus out of the wires, without frear--if they screw up in your misting of them, they will screw up as you hit slush at 70 mph, so spray away!

Cheap/free test--big rewards.

If arcing, replace wires. Retest. If more arcing, determine cause, then replace cap/coil wire, etc....

Also, look for carbon tracks on the inside of the distributor. If present, replace cap/rotor.

Let us know.

Peter