All Small Six New guy with Comet dying leaving a stop

This relates to all small sixes

Revrat

Active member
Good morning, guys. I've got a 64 Comet with a 200 in it. Automatic, 42,2xx miles, runs great at idle and most of the time while driving. It sat for years in a field, so it took me some time to get it going and road ready, admittedly I haven't driven it very much, maybe 30 miles so far. The issue I'm having is it dies sometimes when leaving a stop sign or light. It only does it after it's good and hot, like 15 minutes of driving. It has also tries to die while at speed with no throttle change at all, but only every once in a while, so I can't definitively say it's related, though it feels the same. If I floor it when that happens I can usually get it to stay running.

Car runs great when moving and idles fine at light
Remove foot from brake and slowly give gas, car dies
When it dies it starts up again pretty easily with some pumping
Cap and rotor are clean
Plug wires are all well seated
Points look good
Plugs are pretty new
New (Amazon) carb
Cleaned and lined fuel tank
New fuel pump with new filter, and clear pre-filter, gas is clean
New ignition switch
Grounds are good at battery, engine and firewall
Terminals at coil are tight

I can't tell if it's electrical or carb related so I've been chasing both. I did see some obscure references to this happening because of vapor lock due to carb overheating, but I can't find too many posts to support that. Do I maybe need to build a spacer?

If any of you have had this same issue I'd appreciate any suggestions you have!
 
"Remove foot from brake and slowly give gas, car dies" could be an accelerator pump not squirting problem.
The engine would go lean and quit without a quirt of fuel.
 
Amazon carb....... start by throwing that in the trash, general opinion of aftermarket carbs...

Could be a bad vacuum diaphragm on the distributor.
 
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I agree with chucking the Amazon carb. Rockauto sells remanufactured carbs (assuming you replacedthe stock carb with a compatible unit). When you say "lined" the fuel tank, what exactly do you mean? Often there is debris in the tank and fuel lines that causes issues. Did you clean the fuel line between the tank and the pump? They can corrode inside and restrict flow. Also look for pinched areas - it's not too uncommon to have a pinched line somewhere.
 
Next time it does, restart it and pull over. Check the fuel filter and see if it's boiling/bubbling. If it is, get some DEI heat wrap and insulate as much of the line there in the engine compartment as you can. This took care of my same issue, which was vapor lock. Luck!
 
Thanks for the feedback guys. I got a vapor recovering fuel filter, some 1/4" return line, a bulkhead fitting, a check valve and a 1/4" barbed/ threaded nipple, they should be here tonight. Tomorrow I will try to build a fuel return to the tank that will dump returned fuel through the bulkhead fitting that I'm going to mount in the sending unit plate. Wish me luck! If it works I'll be back with photos.

Now to post an issue with the drum brakes engaging and staying engaged when they get hot.....
 
Thanks for the feedback guys. I got a vapor recovering fuel filter, some 1/4" return line, a bulkhead fitting, a check valve and a 1/4" barbed/ threaded nipple, they should be here tonight. Tomorrow I will try to build a fuel return to the tank that will dump returned fuel through the bulkhead fitting that I'm going to mount in the sending unit plate. Wish me luck! If it works I'll be back with photos.

Now to post an issue with the drum brakes engaging and staying engaged when they get hot.....
A return line on a mechanical pump is almost a must in a hot climate like where I live. Just FYI, the return line can be plumbed into the inlet line anywhere between the pump and tank. I've found the closer it is to the pump, the less effective at eliminating vapor lock after refiring hot in hot weather. It will eliminate the very high pressure that develops in the pump-to-carb line during hot soak. So no hot-soak flooding anywhere, improved after-hot-start vapor-lock the farther back in the system the return is plumbed.
 
A return line on a mechanical pump is almost a must in a hot climate like where I live. Just FYI, the return line can be plumbed into the inlet line anywhere between the pump and tank. I've found the closer it is to the pump, the less effective at eliminating vapor lock after refiring hot in hot weather. It will eliminate the very high pressure that develops in the pump-to-carb line during hot soak. So no hot-soak flooding anywhere, improved after-hot-start vapor-lock the farther back in the system the return is plumbed.
15 minutes to vapor lock sounds like other issues.
 
15 minutes to vapor lock sounds like other issues.
What else do you think could be causing it? The engine is stumbling at idle too, like it’s missing a beat. The cap contacts are clean, rotor and points look new, plugs are good, wires are good and timing is rock steady at 12 btdc.
 
A return line on a mechanical pump is almost a must in a hot climate like where I live. Just FYI, the return line can be plumbed into the inlet line anywhere between the pump and tank. I've found the closer it is to the pump, the less effective at eliminating vapor lock after refiring hot in hot weather. It will eliminate the very high pressure that develops in the pump-to-carb line during hot soak. So no hot-soak flooding anywhere, improved after-hot-start vapor-lock the farther back in the system the return is plumbed.
Thanks Frank, that’s good to know. I may do that and avoid drilling into the sending unit or tank.
 
Has it ever run right with that aftermarket carb?
It fired right up and idled great, but I couldn’t put any real miles on it because I was running a plastic 1 gallon can under the hood until I got my tank lined. It did die then too, but again, not for like 15 minutes of driving.
 
No, vapor lock after the fuel in the underhood area is consumed = fuel supply restriction . Clogged fuel filter, etc.

X2^^
Shouldn’t be any fuel restrictions, I have blown out and flushed the hard line, replaced the sending unit and rubber lines and replaced the fuel pump. I have the pump with the filter mounted to it, but I also ran a pre filter until I was comfortable that the tank liner was working. Nothing ever got caught in the pre-filter so I removed it last night and put a new rubber hose in its place between the hard line to the tank and the pump.

Today I added a vapor recovering filter that’s getting plumbed back to the tank. I hope to have that done tomorrow. If that helps I’ll pull the spacer I installed, which didn’t fix the problem. I’m also going to replace the gasket under the carb adapter that the water line goes through, that one is a vacuum leak for sure. Couldn’t find any other vacuum leaks.
 
Too many carbs are built, whether new, reman, or aftermarket, do not have a correct float adjustment for the application intended. This can be significant to drivability.
The El Cheapo gray-market ones are the worst; from my experience.
 
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carb.

Only time I have ever had anything like vapor lock was 90+ day, heavy city stop and go, overheated and pushing out coolant. Certainly not in 15 minutes of run time.
 
Too many carbs are built, whether new, reman, or aftermarket, do not have a correct float adjustment for the application intended. This can be significant to drivability.
The El Cheapo gray-market ones are the worst; from my experience.
I was concerned about that as well, but when I got it, I disassembled it and went through the adjustment videos from Mike’s carburetors, and everything was dead on, float height, check balls, and slide weight all in place, everything. It may still be the carburetor, I contacted the seller and they sent me another one, I will try it and see if that helps. If it does not then I will get a rebuild kit for the original of 1100.
 
Has it EVER ran right with this carb? Having it put together and adjusted to what an OEM 1100 should be, doesn't make up for low quality casting and machining of an aftermarket one.
 
I will get a rebuild kit for the original of 1100.
This is the best idea yet if the original carb is in good condition physically. Check for play on the throttle shaft where it goes thru the housing especially.
An example of the errors in the china carbs: I couldn't source a YF carb for a 300 that was physically- that is structurally- solid. Got a couple of rebuilds from reputable companies, but not good. Got a Amazon one. Replaced the plastic internals with the originals. It was not pulling vacuum advance when it should, took too much throttle for it to come in. The vacuum hole (port) was cast 1/8" too high in the bore, the throttle plate didn't clear it soon enough to advance at low road speed. I fixed it by cutting a thin grove in the throttle plate directly under the port. But that's the sort of thing that is just unacceptable, and many folks would not know why their response was not the same at off-idle. I'd estimate that less than 50% of the china carbs run correctly out-of-box based on the stories. You're doing the right thing to go thru it before install.
 
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