Boiling fuel

[Rickricca]

Have been having an issue with fuel boiling in the carburetor with heat soak after shut down. 1940 Chrysler Windsor.

I removed lower pans from either side of the motor to improve air flow, and installed a heat shield between manifolds and carburetor.

 

So far, so good

[Don Coatney]

Have you lowered the float level in the carburetor? 

[Rickricca]

float level is at spec

[_shel_ny]

Lower it. That spec is for 1940 fuel formulation.

[jeffsunzeri]

19 hours ago, _shel_ny said:

Lower it. That spec is for 1940 fuel formulation.

What specification has changed to require a lower volume of fuel in the float bowl?

[Plymouthy Adams]

26 minutes ago, jeffsunzeri said:

What specification has changed to require a lower volume of fuel in the float bowl?

the entire makeup and formulation of gasoline along with the cutting with varying amounts of alcohol.....some very interesting reading on the internet explaining this and the winter/summer blends we go through annually.......

[Don Coatney]

31 minutes ago, jeffsunzeri said:

What specification has changed to require a lower volume of fuel in the float bowl?

 

Corn oil.

Table 2.1: Gasoline and Ethanol

	Gasoline	Ethanol
Flash Point	-45°F	55°F
Ignition Temperature	530–853°F	793°F
Specific Gravity	0.72–0.76	0.79
Vapor Density	3–4	1.49
Vapor Pressure	38–300 mmHg	44 mmHg
Boiling Point	100–400°F	173°F
Flammable Range (LEL–UEL)	1.4%–7.6%	3.3%–19%
Conductivity	None	Yes
Smoke Character	Black	Slight to none
Toxicity		Lower than gasoline
Solubility	None	Highly
Reference: The National Institute for Occupational Safety and Health (NIOSH) Pocket Guide to Chemical Hazards

 

 

 

[greg g]

Simply put 50's gas went bang in an internal combustion cylinder, today's goes whoomph.  It evaporates more quickly, absorbs more heat quicker, boils at a lower temp, produces fewer BTUs. Has a slower flame front, And changes formulas twice a year at least in the northern part of the country. 

[Rickricca]

Since I installed the heat shield and improved cooling air flow, I am no longer having the issue.  Thanks for all the info

[Rickricca]

Also cured the sticky centrifical advance, replaced the vacuum advance and set initial timing at 4btc (was 0). Sometimes I forget the basics!

Runs cooler, more power and no boiling fuel

[1941coupe]

And be sure to check your heat riser for proper operation.