Mechanical or Electrical fuel pump
Race Director
Joined: Mar 2017
Posts: 11,931
Likes: 4,497
From: Virginia
Please punch your own numbers into your AI of choice. When I played with Grok, I got:
3-5 fl oz of gasoline in a Q-Jet carb.
It takes 10 BTU to boil off one fluid ounce of gasoline, if you start with gasoline at 100 deg F.
A 400 lb engine at 200 degrees F has about 1000 BTU more stored heat energy than that same engine at 180 deg F. If only 5% of that heat goes into the gasoline, it may all be boiled out of the carb.
Bonus answer from my own experience:
If you follow factory timing with today's gasoline, your timing will be retarded, and you'll be lucky to avoid dieseling at shutdown.
So, yeah. An engine with retarded timing is a LOT more likely to cook the gasoline out of the carb after shutdown. I've seen it happen. It leads to long starts, or no starts (vapor lock). The aluminum sheet earlier in this thread is one crutch that GM created to help address this problem. Modern timing is a better fix (ask @lars for his method). EFI is an even better solution.
3-5 fl oz of gasoline in a Q-Jet carb.
It takes 10 BTU to boil off one fluid ounce of gasoline, if you start with gasoline at 100 deg F.
A 400 lb engine at 200 degrees F has about 1000 BTU more stored heat energy than that same engine at 180 deg F. If only 5% of that heat goes into the gasoline, it may all be boiled out of the carb.
Bonus answer from my own experience:
If you follow factory timing with today's gasoline, your timing will be retarded, and you'll be lucky to avoid dieseling at shutdown.
So, yeah. An engine with retarded timing is a LOT more likely to cook the gasoline out of the carb after shutdown. I've seen it happen. It leads to long starts, or no starts (vapor lock). The aluminum sheet earlier in this thread is one crutch that GM created to help address this problem. Modern timing is a better fix (ask @lars for his method). EFI is an even better solution.
