A check of the fuel discharge nozzles in the carburetor is a better check at that point. You want to see at least a couple good healthy squirts.

If you suspect fuel peculation, mount the Airtex under the cab, along the frame rail Wire it in with a toggle switch. Only you will know it is there.

You may be experiencing crud build up on the points as you indicate five years since replacement.

And how old is the battery? Had it load tested?

Check with Good Sam roadside assistance program. They contract to tow large motorhomes and their literature says they tow any vehicle you own or some such verbiage. They towed my F4 in May. First time out she came home on the hook, (Aftermarket electronic part failure) actually a flatbed, with no mention of restrictions. Only time I've ever been towed and I would rate the experience a 10 out of 10.

 

My 239 y block has been hard to start hot since it's rebuild last year. A couple of weeks ago I got an optima 6 volt battery from summit. 800 cranking amps and it's 1/2 the size of a regular battery. I did this on the recommendation of a friend with a 54 lincoln 368 high compression engine. Went racing the last weekend of June. Started every time. Took a load of electric motors to the scrap yard today. Started twice at the scrap yard. It's hot today. $136.00 and free shipping. Worth a try. Dennis

 

Initially I also thought vapor lock. But that 6v -not enough oomph to fire sounds just as promising. I'd toss in a 12v battery and the cables and when she lays down again try Rusyrelic's starting sequence. But get that Good Sam insurance first?
As far as vapor lock, the old timers I learned under swore to put good old clothes pins on the fuel line. I've never had to try it but seems to me that it would just acting as a heat sink. Can't imagine how well wood conducts heat but they swore by it for the old flatheads? Elec fuel pump sure seems smarter to me, but clothes pins would be more original!

 

The clothespins are really to prevent heat from the engine compartment from heating the hose and therefore the gas. It's kind of an old wives tale, IMO. We have really different gas nowadays.

 

So insulating...?

 

Yes. Wood is a good insulator. I agree tho, electric pumps FTW.

 

I remember the days of the clothes pins, they were used on the steel gas lines and did in fact work. With the use of Rubber hose fuel line, the vapor lock becomes a non issue. The wood acted as a conductor of sorts and actually drew heat way from the metal, the rubber acts as an insulator keeping the heat from the fuel.

 

Wood and rubber have almost the same heat conductivity, which is less than 1% the conductivity of steel, so they are both insulators.

Back to the OP's question...

 

Well my first guess would be the points if they at least four to five years old I'm sure at minimum they need to be adjusted. I would check the points and then check the timing in that order.

 

I once bought a 'series-parallel switch' from JC Whitney. With this device, you run two six volt batteries. There is a solenoid device that picks up the signal from the starter circuit and allows the starter to crank on 12 volts. The 12 volts goes only to the starter, nowhere else. Once running, the system is all 6 volts again. It worked for my hard starting truck in the late 70's. Sort of a last ditch effort, but thought I'd put it out there. It was made by a company called 'Orpin' if I remember correctly.

 

My 50 F-3 V8 is hard to start when hot or when it has been sitting for a couple of days. I converted it to 12V and kept the 6V starter, so it really turns over fast. But even though the starter probably turns it over faster than an idle, it still has trouble starting!
I just read about using the proper version of power valve in the carb to prevent hot start problems. I read a short article on this in MACs catalog online I think. It costs $9. as I recall.
On my truck after it sits a couple of days in the garage, it will start instantly if I pump the pedal once to squirt gas in. Then it dies even if the choke is used. I suspect the float bowl is empty. Hmm, maybe the power valve is leaking the gas away.
Update: Ok, after sitting in the garage for a week, I pulled the top of the carb and the float bowl was empty. I poured some gas in it and covered it and it dropped 1/4 inch in an hour. I am going to get a new power valve for it. Patrick

 

So as soon as the insurace office opened this morning, I called in with my roadside assistance horror story. The represenative was very understanding of the mess and informed me that the roadside assistance dispatcher had incorrect information and told me as far as she was aware, my vehicles, allthough big and heavy, were covered. It just may take longer to get service and a flatbed may not be guarenteed. Regardless, she raised my case to the roadside assistance lead to get a definite response.

 

If your battery is slowing down spinning after 6 or 7 revs. I would suspect you do not have enough voltage left over to start the truck. Be sure all of your grounds are clean and tight and you have large cables. You can check the voltage at the ignition side of the coil. I would suspect if you check it while trying to start the voltage is around 2 volts or less. You will need to check the battery to make sure it is really taking a good charge and is full voltage. The 6 volt system works great as long as everything is right but let one area get slightly weak and they can fail to start.
Good Luck
Larry

 

Not slowing after 6 or 7 revs, but after that many start attempts. Regarless, the current battery is atleast 6 years old, so I picked up a new one today. I plan on taking her out to a cruise night tomorrow provided the weather cooperates and that I don't hear anything contradictory information from my insurance.

 

A local shop I do business with says they're having the same problem with any vehicle that still has a carb. He claims the current gas is made for fuel injected cars which have pressure to keep them from vaporizing. In the float bowl, there's no pressure so the fuel boils off when it's hot. Spin the engine a little to fill the bowl and it'll start. I've noticed the same thing with my truck. He says they have no solution unless you can find different gas.