'66 Ford F-100 4 speed 390

Having a hard time getting the truck started after it's been run awhile.
Does anyone know why this would be. Battery is strong. I'm thinking possibly the starter, but I haven't had any issues starting a cold engine?

Thanks, Bob

 

Are you running headers? how close is starter to pipe? Heat shield might be in order.

 

Bob, Sounds like the same issue that I had after I installed alum. intake and 4 barrel. It was boiling the gas out of the carb.

A 1" phenolic spacer under the carb solved the issue. It has helped several others that have had the problem.

John

 

Define your hard start.

Slow cranking? Won't crank? Cranks but doesn't fire? Starts and dies? Give us a hint.

SPark

 

I agree with John, especially if you run the Edelbrock 4 barrel cab. Aluminum conducts heat a lot faster than iron does, when I had an Edelbrock it would do the same thing, you would have to crank and crank and crank to get it to start. I switched to a Holley and a lot of the problems went away. I installed the spacer on mine but I found a 1/4 inch one verses the 1-inch. Never had that problem again.

I also installed an electronic conversion kit to get rid of my points and used that with my MSD 6AL box and that made a noticeable improvement on the starting of my pickup.

As for headers if you are running them or plan to I would buy or have them ceramic coated. I bought a set from Dyno-max 8 years ago and I have never gone through a starter. Now for the last 5 years this has not been a daily driver but I have never had a starter problem. Plus they still look good, mine have dis-colored a little from leaking oil that got burned on to them but other wise they look good verses the painted headers that peal off in the first 5 minutes you drive them and rust. The right hand header wraps right around the starter and I beleive the painted ones allow a lot of heat to the starter, the ceramic coated ones allow the heat to exit the pipe and less of it dissipates through the tube of the header.

Jeff

 

Thanks everyone!
Cranks but doesn't fire...or takes forever to fire.
I have headers. Have a holly 4 barrel carb. Not sure what the intake is made of. But I think I'll try the spacer first, then maybe the heat sheild.

I appreciate all your input.

~Bob

ps) have electronic ignition

 

My starter is only about 1/4" away from the headers. Would a shield even fit in there, or would I have to wrap the pipes?
~Bob

 

A starter blanket is always a good thing to have. IMHO



John

 

Update:

The carb already had a 3/4" spacer under it, so obviously, a spacer isn't the answer. I haven't tried wrapping the pipes yet, although I did pick it up.

New problem arose, so this is now on the back burner.

My carb is having issues...I should say, I'm having issues with my carb,
To make it run smooth between shifts, meaning no hesitation when stepping on the gas after a shift, the idle has to be set really high....almost 2000 on the tach. And if I have my tach at about 1,000 to 1,200 it idles great, but hesitates between shifts. Do you think that means it's not getting enough gas?...too much gas?...maybe needle & seat need to be replaced in the carb?

Thanks, Bob

 

Bob, Is the spacer metal?

John

 

Hey John,
Yes, it is metal.

 

The metal spacer doesn't help the problem. It just transfers the heat. You need a phenolic, fiber or wood spacer to act as an insulator.

As for your idle between shifts, you probably have a vacuum leak or your carb needs a rebuild. When you say it hesitates, is it when you step on the throttle or does it start to go then fall on it's face. If you are driving along and step down, does it go or does it hesitate? Does it blow a cloud of black smoke out the exhaut when you accelerate (not blueish oil smoke, black carbon smoke)?

This could also be a distributor problem with bad/stuck advance or an extremely worn shoft.

It could be a ton of tuning things with the carb (pump cam, squirters, accelerator pump, power valve, base gaskets), or it could be the same issue the spacer can help with. You may be on the edge of vapor lock and the higher idle pulls enough fuel through. Does this happen all the time or just when the motor gets up to temp or hot?

How old is the carb, has it sat a lot, has it backfired when trying to start it?

Unless you have a radical cam with a ton of overlap, you should be able to idle below 800 RPM. Our full roller race motors idle just fine at 1100RPM and they have a ton of lift and duration.

SPark

 

When you say it hesitates, is it when you step on the throttle or does it start to go then fall on it's face.
when I step on the throttle

If you are driving along and step down, does it go or does it hesitate?
hesitates, almost like a hiccup, then takes off
Does it blow a cloud of black smoke out the exhaut when you accelerate (not blueish oil smoke, black carbon smoke)?
No
You may be on the edge of vapor lock and the higher idle pulls enough fuel through. Does this happen all the time or just when the motor gets up to temp or hot?
All the time
How old is the carb, has it sat a lot, has it backfired when trying to start it?
Carb age ? Has never backfired.

Thanks for your help!
~Bob

 

Since it does it all the time, you have a problem with the power valve or the squirters or the accelerator pump.

Has this carb always done this or did it just start?

If it just started, I would change the power valve first. While I had the float bowl off doing the power valve, I would put in a new accelarator pump because it's cheap and easy then to do it. Both are available without buying a kit. My guess is a bad power valve. They go bad from time to time, dry out and crack. Same for the accelerator pump. The hesitation points towards those areas.

Without any puff of black smoke, it's not overly rich and having to clean itself out. You are experiencing a lean condition or a lack of fuel during the transition from acceleration circuit to the power curcuit. That's where the power valve comes in.

If it's done this all along, you will need to get into the pump squirters.

My money is on a bad power valve. It will dump gas at the wrong times and not cover that period when the carb goes from the idle circuit to the power circuit.

SPark

 

I am having the what sounds like the exact same symptoms on my slick - I replaced the old autolite carb and put on a brand new Holley 2bbl. Ran better but still had the hesitation. I verified that the timing was right on. Checked the accelerator pump,it was working like it should. Than I said screw it and decided to crank up the timing until the the idle smoothed out real nice. Then I took it for a spin and most of the hesitation was gone! It still has a little bit though, so I may try to crank it up a little more.

Try adjusting your timing. I thought mine was set correctly, but I guess sometimes the balancer slips over time and gives you the wrong reading. Trust your ear, not the balancer. Just be sure to listen for pinging and back it off a little if you hear some.