Well the weather here central FL has finally settled down enough to get some great road time with the 66. I have run into a problem.
The car starts first time, everytime when cold, but sometimes (often) when it's hot and been sitting a while, it will crank and crank before it will run. Only thing I've been able to tell is it is not loading up from the carb as when it does start there is no smoke or rough idle.
This engine had about 600 miles on it since a complete rebuild, and is running an Edelbrock carb rather than the Holley.
What should I check next?
Thanks,
Joevette

 

Maybe it's a vapor lock issue, or the starter gets heat soak. Does it seem to crank over easy when it doesn't start, or hard. I would check the starting circuit, starter, cables, battery, etc.

 

Skids,
Heat sink in the starter is not the problem, engine will turn over very easily. Have thought about vapor lock, but won't a vapor lock usually go away after the car sets a bit? I have let the car set for 30 - 60 minutes and still had the problem. I'm thinking maybe something electrical? Coil maybe?
Originally, the electric choke was attached to the coil for power. I have since moved it to the bottom side of the ballast resistor. When I though that might be the problem, I bypassed and rewired to a post on the fuse block that has power when the ignition is on.
Might the time it was connected to the coil damaged it?

 

I experienced this problem on some other chev models. On at least two occasions it was percolating.

The float level, set just a little too high causing the hot fuel (which gets a little warmer when you shut the car off) to expand and drip into the manifold, basically flooding the engine.

Just a thought. I fixed the problem on a couple of time with a simple float adj.

Mike S.

 

Classic symptoms of flooding or percolation. My vote would still be for that.

 

Agree with percolation. Get it good and warmed up, like 15 miles of driving or so, park it, and let it sit with the hood closed about 10 minutes or so. This gets the fuel bowls good and heat soaked. Then open the hood and remove the air cleaner. You'll probably be able to hear the fuel boiling in the bowls. This makes it drip down into the intake through the boosters. Conventional wisdom holds that today's gas has a lower boiling point than that back in the day. I never heard of float adjustment as a cure, don't think it would work if you are really getting boiling as I was. What you need then is a heat shield or insulating carb spacer. Holley and Mr. Gasket make the heat shields, which raise the carb very little. Various folks make wooden or phenolic insulating spacers, which keep the carb from heat soaking through conduction with the manifold. Another trick you could use which is invisible is to block off the heat riser ports by using intake gaskets that have the ports blocked. This is a bit of a job, but will keep the intake and carb much cooler while looking stock. Be sure to gut or wire open your heat riser if you do this, otherwise the closed heat riser will be trying to direct exhaust gas into a closed-off heat riser port when the engine is cold. To maintain stock appearance, use a cutoff wheel to remove the flaps inside the heat riser valve. Since you're in Florida, you don't need the heat riser anyway.

 

My car did the same thing. Lowered float level, problem solved. By the way the floats were at the manufacturers specified level and I went below that. What's up with todays gas?

 

Thanks for the replies.
The carb already has the heat spacer on it. Also, are the floats on the Edelbrock adjustable? I know well how to adjust the floats on a Holley, but don't beleive this baby has any.
If the gas is percolating, is that something you could smell? I know when I've had carbs where the float stuck, you would definitely smell it. There is no fuel odor in this case.
Funny, of all the Vettes I've owned through the years, this is the first time I've ever had to deal with this.
I won't be able to drive it for a few days but will check out everything suggested here and report back after I do.
Thanks again!

 

Next time you go for a drive, take a good spark plug with you. When it doesn't start, pull the easiest to get to plug wire and snap it on the plug and see if it fires. If it does, your ignition is probably okay. Pull the air cleaner top and open the butterflies all the way. If the floor of the intake has gas standing in a puddle, your carb is boiled over.

Yes, the Edelbrock has a float adjustment. You have to bend the float arm. No external adjustment.

 

Joe,
To adjust the floats on the Edlebrock remove the top to get at the floats then you litteraly bend the metal mounting tabs on the floats to get them where you want. I found the instruction on the internet and did it myself. It's very easy, I'd say a one on the tech scale.