1965 Coronet 361 2bbl hard start when hot

[finz68]

My 65 has 48k miles with an all original 361 2bbl. The weather has been in the mid 80's in New York and the last 2 times I drove it between 10-20 miles (normal water temp reading) and then turned the ignition off for maybe 20 minutes. Trying to restart the car, it almost ran my battery down with all of the cranking necessary to get it to run. When it did finally catch it ran very rough, almost stalling and then in about 30 seconds it idled and accelerated fine. Same scenario both times. Air filter is clean, points and plugs were changed about 2 years ago (300 +/- miles maybe) and the fuel pump was replaced less than a year ago. 87 octane and lead additive used. Any help would be greatly appreciated.

 

[eldubb440]

probably leaking gas into the intake after shutdown........ dark smoke upon restart? hold the pedal down while cranking, don't pump it

 

[finz68]

probably leaking gas into the intake after shutdown........ dark smoke upon restart? hold the pedal down while cranking, don't pump it

I'll try that, thanks!

 

[Mopars & Missiles]

Change the stock valley pan to one with a blocked off heat crossover.


(assuming that you don't drive it during the winter months).

 

[Mopars & Missiles]

Also when starting a hot engine, open the throttle plates some instead of trying to start with throttle plates closed (idle position). DO NOT pump the pedal, just depress part way and hold while cranking.

 

[R413]

You could have a leaky needle and seat.

Try leaving the hood open when you park so the heat can get put.
try using ethanol free gas, it will help this problem.

Open this link and click your state at the top
Pure-gas.org - ethanol-free gasoline in the U.S. and Canada

 

[pnora]

1-Make sure the choke is open.
2-As said hold the pedal 1/4 to 1/3 open and keep your foot there even if you stop cranking. Then crank it again.I have seen people pump the pedal when they said they were not. Might be a habit.
3-Consider a mini starter. They do work.

 

[Unkle Krusty]

My 318 likes the go pedal to be pressed on, to about one quarter the way down. It fires almost right away.

 

[Geoff 2]

With 48K miles, you WILL have a worn needle & seat. That raises the fuel level in the carb & could make the mixture very rich when the engine is hot. Get a new n& s, install, & adjust.

 

[Gold Rush]

Isn't that also a symptom of bad coil? Never had one do that myself but I seem to recall several reports of coils causing that issue.

Good luck finding and fixing it.

 

[finz68]

Also when starting a hot engine, open the throttle plates some instead of trying to start with throttle plates closed (idle position). DO NOT pump the pedal, just depress part way and hold while cranking.

Thank you!

 

[mtbase]

I have a 66 361, never experienced this issue on this engine.
BUT, your symptoms match an issue with another, similarly constructed, engine's fuel supply. This may, or may-not help...
The rod that drives the fuel pump had worn. It was actually .110" shorter than the new one purchased/replaced. Same thing: could drive almost anywhere, with no issue, but shut it off for 15 mins and holly crap! It eventually started having problems after exiting the highway. I spent a lot of money having mechanics "check it out", to no improvement. A service manager gave me that suggestion, it made the difference for me.

Best of luck

 

[finz68]

I have a 66 361, never experienced this issue on this engine.
BUT, your symptoms match an issue with another, similarly constructed, engine's fuel supply. This may, or may-not help...
The rod that drives the fuel pump had worn. It was actually .110" shorter than the new one purchased/replaced. Same thing: could drive almost anywhere, with no issue, but shut it off for 15 mins and holly crap! It eventually started having problems after exiting the highway. I spent a lot of money having mechanics "check it out", to no improvement. A service manager gave me that suggestion, it made the difference for me.

Best of luck

Thank you! Even though when I eyeballed the new pump with the original and all looked the same, I realize that little difference would not be noticed. I will seriously consider your suggestion.

 

[pnora]

I have a 66 361, never experienced this issue on this engine.
BUT, your symptoms match an issue with another, similarly constructed, engine's fuel supply. This may, or may-not help...
The rod that drives the fuel pump had worn. It was actually .110" shorter than the new one purchased/replaced. Same thing: could drive almost anywhere, with no issue, but shut it off for 15 mins and holly crap! It eventually started having problems after exiting the highway. I spent a lot of money having mechanics "check it out", to no improvement. A service manager gave me that suggestion, it made the difference for me.

Best of luck

That rod would have zero impact on a car with a hot restart problem.

 

[toolmanmike]

Isn't that also a symptom of bad coil? Never had one do that myself but I seem to recall several reports of coils causing that issue.

Good luck finding and fixing it.

That could very well be. When it acts up the OP needs to check for spark and look down the carb to check the accelerator pump squirt for gas in the carb. Any troubleshooting tree in a service manual starts there for a no start condition.

 

[pnora]

That could very well be. When it acts up the OP needs to check for spark and look down the carb to check the accelerator pump squirt for gas in the carb. Any troubleshooting tree in a service manual starts there for a no start condition.

A lot of these cars were temperamental on a hot restart. Most of the time its a hot perk that causes gas to boil and put the car into a partially flooded mode. Lots of things to look at. One overlooked is a stuck closed heat riser valve. That will bring the carbs temps up drastically and aggravating a already partially flooded condition.

 

[Don Frelier]

Retarded timing makes for poor hot starts as well.
But it sure seems like a vapor lock/fuel boiling type issue.
Can you get ethanol free 90 in your area?
It might help.

 

[finz68]

That could very well be. When it acts up the OP needs to check for spark and look down the carb to check the accelerator pump squirt for gas in the carb. Any troubleshooting tree in a service manual starts there for a no start condition.

Funny you just posted this, I just opened my laptop to look for a new coil!

 

[finz68]

Retarded timing makes for poor hot starts as well.
But it sure seems like a vapor lock/fuel boiling type issue.
Can you get ethanol free 90 in your area?
It might help.

No ethanol free by me. Should I put higher than 87?