I guys,,,,I have a 1972 F600 dump with what I belive to be a 361 it has the holley 2bbl and manual tranny. My problem is the truck will run fine at any rpm as long as you hold it steady. For example it will idle at 500 rpm just fine. But the minute you try to give it any throttle is spits and sputters and wants to die. If I step on it hard and say get it to 1500 rpm it will again run just fine as long as I hold it steady, but as soon as I try to give it any gas,,,same problem spitting and sputtering. Again if I hit the throttle hard it will have a fit and backfire thru the carb, but it will clear out and grab rpm. This is my uncles truck and he said it has done this for years. I rebuilt the carb today casue it recently started dying on him. The fuel bowl was full of junk and the needle valve was sticking some. Anyway the dying part is taken care of, but I would like to get it running better, cause I'm going to be using it alot here shortly. I've got a new holley 350 cfm carb I'm throwing on it tomorrow, but this seems to me to be an ignition problem. What do you all think??

Also on the dist. there is a vaccum line in addition to the one for the vaccum advance. It runs to the left side of the carb and screws into the carb. What is this for.

Thanks
Bob

 

It sounds like it needs a good tune up change out the points change the cap and rotor new plugs and wires.

 

I'm going to take a stab at this for you.

If you think it's an ignition problem than install an electronic ignition conversion into the distributor and add a high output coil. They both ought to be about $120 in total. You'll love how easy it starts with the HO coil.
Then as Kenworth suggested, do a full tune on it. Plugs, wires, cap and rotor, ect.

You want to make sure the timing is correct and if you have the know-how, change the mechanical and vacuum advance curve to a quicker advance curve. Your engine probably only has at best 8 to 1 compression so you should be able to run a real quick curve without any issues. Make sure it's done correctly and won't exceed 36 to a maximum of 38 degrees mechanical advance at the top of your RPM range.
Wouldn't be a bad idea to simply dump the dual stage vacuum advance and get a single stage (normal) vacuum advance unit. Make sure to hook the vacuum line for the vacuum advance to a carb port with vacuum that increases with the RPM. Most Ford vacuum advances can be adjusted by inserting the correct size allen wrench down the small tube of the advance where the hose attaches to it.

Got a friend with an International that has some sort of morphidite Holley and it was doing the same thing. I ended up swapping the squirter in the venturies to a larger size and adjusting the slack out of the fuel pump lever on the front corner of the fuel bowl that acts like a lever. Made a huge difference, ain't perfect but loads better.
I'ld try hard not to make the engine backfire, the power valves in Holleys are very susceptible to damage when it happens. Most of the new Holleys have blowout protection for engine backfire but one as old as yours probably won't.

All that should make it's drivability and quite possibly the economy much better.


Good luck with it.

 

Accelerator pump ????

 

I agree on the Accelerator Pump. That's what it's there for- to provide an extra shot of fuel to help the engine accelerate. If it's not working your air mixture is turning lean as the throttle plate opens and allows more air in but the fuel flow remains constant. That's what the popping is- a lean mixture. The accelerator pump provides that shot of fuel to cover the transition period until more fuel starts flowing through the carb venturis.

 

Power valve

 

New Holley and timing took care of the problem. I forgot to mention that it appeared to have a new cap, rotor, and wires. I threw the new carb on and the truck ran alot better. It still stumbled badly when I hit the gas, and started a little hard. So I disconnected the vacuum advance to time it and then it didn't even want to start and run. I advanced the dist, hit the ignition and it fired up, and then went about timing it. Seems the last person who gave the truck a tune-up must have timed it with the vacuum advance hooked up.

Also as far as the other carb,,,,I put a kit in it which included a new accel pump and power valve. So I really don't know what was wrong with it. Maybe a warped metering plate???


Thanks
Bob

 

Sounds like what I'm up against. My '73 F600 has a 391 with a holley 4 barrel (list # 6945) I think that this is a governed carp to go with the Hydro vac brakes that I just yanked out in opt for the school bus brakes out of a '76. I have three vacuum lines going from the distributor to the carb and I'm thinking about canning the whole set up for a mallory intrigal electronic ignition distributor and an edelbrock 650 cfm carb. I already have one of those monster coils from accel.

Make any sense?

 

If you can locate a decent used pick-up or car distributor from a 360, 390, or any FE series motor, just use that. Throw a Pertronix Electronic Ignition conversion in it. Make sure it only has one vacuum line to the vacuum advance or replace the existing one with a single diaphram advance. It's not a bad idea to recurve the distributor to a quicker advance as well while it's out.
Got the Mallory Unilite distributor in my 72 F250 4X4 with a 390 and it has been an excellent unit.

Edelbrock carb will be fine just won't be real fuel efficient (probably no worse than the Holley). You'll also lose the throttle lock aspect that was on the Holley but who cares.

The Accel Super Coil is way more coil than I would use. You can get a cheapy from Summit that throws about 45000 volts for like $26 and not have to contend with adding resisters or special mounting. Just swap it out and enjoy!


iowabowhunter;
Great news on your rig, sounds like you got a decent grip on the situation.

 

Those carbs can be a real pain when they start show wear and age.If you can still find a master rebuild kit for it which it takes to make it work properly again ) you would probly have to mortgage the farm to buy it

 

Personally I love the Edelbrocks,,,,that is all I run, but would you be able to run an 1850 on there?? I belive they are still reasonably priced.

 

Search Results for holley 1850 - SummitRacing.com

 

How bout this

Edelbrock 9906 - Edelbrock Performer Remanufactured Carburetors - Overview - SummitRacing.com

 

Thanks for the info guys. I appreciate your help.