Carb/Fuel Hot Start Problem 427/400 4spd. with A.I.R. without A/C

[Jack C.]

Great battery, great starter good fuel, good TI system........From a cold start with the choke closed, the car starts up within 3 or 4 seconds and goes into fast idle. I then kick it down to curb idle. I then can run the car for some time at operating temps. After a while running it. it will stall when I drive to a stop or if I shut it off voluntarily it will only crank and not start. 15 minutes later it will start again after it sits. The float level is good, no leaks, good fuel pressure, new fuel filter, new thermostat, new ctr. carb base gasket, the car is not overheating. It idles at 750. The engine is not getting that hot to cause a vapor lock but that's what it seems to be. Any suggestions?

[Terry M.]

Re: Carb/Fuel Hot Start Problem 427/400 4spd. with A.I.R. without A/C

So long as you are substituting new parts as a troubleshooting method -- throw a new coil at it. Hot coils do strange things.

[Jack C.]

Re: Carb/Fuel Hot Start Problem 427/400 4spd. with A.I.R. without A/C

That was an item that crossed my mind as being the culprit.

[Rich P.]

Re: Carb/Fuel Hot Start Problem 427/400 4spd. with A.I.R. without A/C

Hey Jack,
I have had several Tri Powers that would run between 190-210 and because of the low boiling point of todays gas they get vapor lock. Does it do the same when you run cam 2 or AV gas? That would be my starting point (after the coil like Terry said).

Rich

[Jack C.]

Re: Carb/Fuel Hot Start Problem 427/400 4spd. with A.I.R. without A/C

I spoke with Dave from TI Specialty. He gave me a few tips which steered me in the direction of the coil or voltage that might be the issue. I'll try his replacement coil first.

[Richard T.]

Re: Carb/Fuel Hot Start Problem 427/400 4spd. with A.I.R. without A/C

If the coil doesn't fix the problem try running AV gas or some race gas through the system. The ethanol in todays fuel will percolate when hot and cause this problem. here in New Jersey all the stations sell anymore is gas blended with ethanol. My 62 F.I. will run fine on pump gas in cooler weather but once it warms up the trouble starts. I run AV gas in the summer, it doesn't eliminate the problem but makes it better. Good luck Rich

[Joe R.]

Re: Carb/Fuel Hot Start Problem 427/400 4spd. with A.I.R. without A/C

OK, lets try another approach! Tri-power trouble!!!! After running the BB for a while and the monster is good and heated up pull it under the carport. With it not running give it a couple of minutes and remove the air cleaner. Observe which carb is smoking a little. One or more of the carbs are leaking when hot and making the BB run a little rich. Probably the offending carb will be black inside and you may be able to see gas running down inside past the butterfly's. Just find out which one or more and you will have fixed the problem after a rebuild of the wonderful Holley!

JR

JR

[Jack C.]

Re: Carb/Fuel Hot Start Problem 427/400 4spd. with A.I.R. without A/C

Richard. Joe. I do use avgas. All three carbs look really good and no visable leaks. A member mentioned that the replacement TI coils may not be all that what they are suppose to be. Mine is over 5 years old. TI Specilty has one one that mirrors the original ones from a performance standpoint. I'm going to give it a try.

[Rich P.]

Re: Carb/Fuel Hot Start Problem 427/400 4spd. with A.I.R. without A/C

2 things I agree with Joe. Many a tri power carbs "Leak down" when hot. Like joe said you will see steam rising from the culprit. and you can see gas dripping from the venturi. Check the metering plates and re tighten make sure the floats dont let expanding hot fuel drip into the carb body. second did you try straight cam 2 to just see if that helped.

[Clem Z.]

Re: Carb/Fuel Hot Start Problem 427/400 4spd. with A.I.R. without A/C

block the exhaust heat riser crossover that runs thru the intake manifold under the center carb to get rid of the exhaust heat. since you can not take those newer fuel pumps apart like the old ones to drill a .015 hole in the valve body to let the pressure between the carb and the fuel pump be released back into the input side of the pump as we did with a older corvettes blocking the crossover is the only thing that will work. i have fabricated a bypass between the pump out put and the the pump input using a .015 restrictor but this requires modifying the fuel lines. if your gas tank has a non vented cap try a vented one to relieve the pressure in the tank caused by muffler heat to the gas tank

[Rich P.]

Re: Carb/Fuel Hot Start Problem 427/400 4spd. with A.I.R. without A/C

Clem,

I'm interested to know if blocking off the plate will affect the choke operation. Whats your past expriance with that.

Thanks, Rich

[Clem Z.]

Re: Carb/Fuel Hot Start Problem 427/400 4spd. with A.I.R. without A/C

Clem,

I'm interested to know if blocking off the plate will affect the choke operation. Whats your past expriance with that.

Thanks, Rich

yes it will but i just disconnected the choke as you do not need it unless you keep your car out side in colder weather. a few pumps if the gas and it will light right up. here in Pa even in the winter i drove all my aluminum intake cars with no choke.

[Jack C.]

Re: Carb/Fuel Hot Start Problem 427/400 4spd. with A.I.R. without A/C

I tried one of TI Specialty's coils and it seems to have done the trick. Started the car and ran the engine several times at operational temps and the car never stalled out like before and started right up. Took the car out tonight for a shakedown run and returned to the house and left it at idle in the driveway. It didn't stall out and started right up after shutting it down. My thanks to Dan Andrews for loaning me a carb to help eliminate that question and to Terry M. and Dave Feldier.