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Toms55cp
New Driver

ethanol fuel

Having an issue with my 55 Chevy cp 265 v8 2bbl.  After an extended drive in warm weather (an hour or more) the fuel in the glass bowl filter starts to bubble and empty down about half way, fuel pressure is good (4.5 psi). Engine is not overheating,( temp is around 185 degrees) At times engine will surge on accel and stall out and will be difficult to restart. After a short cool down car will restart. Have found very weak accelerator pump spray when condition occurs,( carb has an ethanol resistant accel pump) I assume the fuel is boiling when I have this condition. I have since removed the glass bowl fuel filter and it has seemed to help. No ethanol free fuel is available in my area. I have been adding Sta-bil 360 after each fill up. Any other suggestions would be appreciated, thank you

4 REPLIES 4
TG
Gearhead

I am not a big fan of ethanol fuel - but largely because I feel like I am paying more for a fuel with less energy content. With that said, however, I think ethanol mixes get more of a bad rap than they deserve. What I can tell you about ethanol is that it is very good at cleaning deposits from your fuel system and depositing them as a crust ring in your carburetor. This is a fairly limited time affair, and only an issue if you drive your vehicle infrequently as eventually the ethanol will clean everything out an all is fine

 

Most of what my friend Mr. Google tells me is that ethanol actually has a higher boiling point than gasoline. Your vapor lock issue probably predates the advent of ethanol blended fuel. What I would do in your scenario is look at how your fuel line is routed, and make sure it is not too close to an exhaust pipe, header tube, etc. Other modification-oriented ideas you can try is installing a fuel pump with bypass (some fuel gets sent back to the tank) or install a thick spacer gasket between the carb and the motor. A lot of older engines send exhaust through the bottom of the intake manifold to help cold engines vaporize fuel better. On a warm engine, this can lead to a hot carb and vapor lock. If you are really looking to modify, block that exhaust passage up all together. I have done it on many a car. I seriously doubt if you are going to be driving your classic when it is 14°F out

Toms55cp
New Driver

TG, I have owned my 55 for just about a year now and did not have this issue until this summer. As far as any deposits from the fuel system, I have replaced the fuel tank, fill neck and both fuel lines with stainless steel. Any debris I think should be minimal. There is enough clearance between the fuel line and exhaust manifold and I do have the fuel line wrapped with heat resistant material. Was thinking about the carburetor heat insulator. I may try blocking off the exhaust crossover passage. Thank you for your suggestions.

Sajeev
Community Manager

I would wrap the fuel line in heat resistant material (kind of like header wrap) to keep the ethanol fuel flowing, and consider installing an electric fuel pump.  Both can help, but there are no guarantees unfortunately. 

Toms55cp
New Driver

I do have heat resistant material on the fuel line to the fuel pump. I  would rather not install an electric fuel pump  as I would like to keep the car as original as I can. I may have no other choice, But I will keep trying............ Thank you