I'm sure someone that knows more than I do will chime in but it sounds like vapor lock.

 

I was kinda thinking vapor lock too, like maybe the new gas I put in before the issue started had water in it or something.

 

There is always the chance of water contamination, especially if refueling during a station's resupplying it's tanks. Vapor Lock stems from excessive engine heat transferring to the carb's fuel bowl, wherein, the fuel begins to vaporize. This can occur after one shuts down the engine and it "heat soaks". Excessive heat can cause the starter to "drag" (be slow to turn) when one attempts to crank the engine. The internal parts of the starter begin to swell. Especially if running headers and the collectors are near by, as is in most cases. In many cases simply waiting a bit, parts will cool down. Hope this helps.

 

Any other thoughts?

 

Do you have a phenolic separator between the carb and intake? If not, add 1/2", if possible, so we can rule out vapor lock.

 

Thanks kenash.
There is a spacer. The mystery is though why did it all of a sudden start happening after years without issue?

 

This is why we try to rule out conditions. Was these circumstances(weather) more severe and the subsequent activities different than previous years?
Is the spacer phenolic?

 

Plugs loaded up while idling for too long? Have you checked them?

 

I’ve seen it...on my own car. Not saying that is your issue, but they are easy enough to check.

 

I will pull the plugs this weekend and take a look. I have drivin it in very hot weather before and, when it has been very hot out, it has shown signs of vaporlock after heatsoak. But that has only happened 1 or 2 times ever in extreme circumstances.
It seems to be doing it now everytime its warm.

 

This is one of the advantages of having an electric pump back at the tank.
If all the fuel evaporated from the carb, turning the key on and the pump on will fill the carb with fuel without having to crank the engine.
And sometimes the fuel in the line from the tank turns to vapor. The mechanical pump on the engine can’t effectively pump a gas the same way it does a liquid. An electric pump back at the tank will slightly pressurize the line, keeping gasoline a liquid.

 

I agree 1ofamillion, I am not driving it enough this season. between "stuff" to do and rainy weather it has really pinched my car time this year.

I am going to take a look at the plugs and then just drive it as I just filled it again and added a can of Seafoam.

"Best thing is anyone with a re-start problem- after driving a while take off the breather and look down carb just after/during ignition off."

What am I looking for ?

 

I'm thinking the poster is referring to fuel droplets spilling out of the fuel bowl air tube. This comes from overheated fuel that's percolating out of the bowl. You can see it, if it it's going to occur, just after you shut down. Or maybe out of the atomizers?

 

I am in the process of getting a 302/2bbl back on the road. I had some issues with it running good one minute then hard starting when warmed up and or surging type idle but once moving I could always drive it. Most of what I read said vaporlock or vacuum leak. After some digging, I found my powervalve was leaking. I have replaced that and have about 200 trouble free miles on it right now. Just thought I'd throw that out there as I looked at a lot of different things before getting to where I am today.

 

So I am 1/4 tank into fresh gas with a can of Seafoam added and no improvement. It does act like it's vapor-locking because, when it's cold, it fires immediately. Even if I let it cool for a couple hours it fires right up.

So why would it run great for 3 years and all of a sudden, literally overnight, it decides it's going to vaporlock?
I guess I will be doing some reading on the causes.

I had a thought, would my Pertronics be having an issue when hot?

 

It would be easy enough to check. When it occurs, remove the coil wire at the distributor place near a ground, crank the engine and look for spark. Otherwise, replace the Pertronix unit with your old point set an see if there is a change. There have been reports of the Pertronix units going bad, not sure which model is more susceptible to the failures. But, I've been running the Pertronix Ignitor 1 for 14 years, have yet to have a problem with this one......Yet?

 

My "guess" is you have either a bad needle/seat or something (chunk of debris) holding float needle offseat. Having to floor it start is telltale. When you shut down fuel pump pressure bleeds off overflowing the bowl(s) and floods the engine. Percolation will be same symptoms. Flooded engine. Hence startup on foot to floor. Vaporlock is the opposite. No fuel. You say it starts fine cold. Classic symptom of flooding/heat percolation.

 

Thanks guys.
Been reading tonight and I will start with the fuel filter and carb cleaner. If that doesnt work I guess my next move would be the fuel pump, I still have the stock mechanical type and its cheap enough to replace.

I do believe it's either flooding or vaporlock.

 

Update...............
I haven't had much time to drive the 67' this summer but I put about 100 miles on it Saturday in 90 degree bumper to bumper traffic, idling, and highway driving. Seems like my hot start issue is cured. Started a few times without issue.

I believe it was bad gas as I had just filled up before it started to act up. I replaced the fuel filter, tapped on the carb near the bowl in case something was sticking, and sprayed a bunch of carb cleaner while running.

I hope that's the end of that.