Fuel boil off

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harvenator

harvenator

A fish called Wanda
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I've been playing with my newly rebuilt 273 with a 600 CFM Eddy on top of a 3/8" insulator. After too much tuning I think my hard start when hot problem is because of fuel boil off. If I try an immediate restart there is no problem. Cold start is also excellent but after sitting about an hour it starts real hard. I'm thinking I might be getting boil off. Any comments before I go out and buy/install an electric fuel pump?
 
harvenator said:
I've been playing with my newly rebuilt 273 with a 600 CFM Eddy on top of a 3/8" insulator. After too much tuning I think my hard start when hot problem is because of fuel boil off. If I try an immediate restart there is no problem. Cold start is also excellent but after sitting about an hour it starts real hard. I'm thinking I might be getting boil off. Any comments before I go out and buy/install an electric fuel pump?
Click to expand...

How much initial timing do you have?
 
I had the same problem. Turns out it wasn't fuel related at all. It was the reluctor gap in a brand new dizzy. Easy enough to check before you do anything else
 
fklskv said:
I had the same problem. Turns out it wasn't fuel related at all. It was the reluctor gap in a brand new dizzy. Easy enough to check before you do anything else
Click to expand...

X2, but not in my case. That's easy to check, just check spark quality CRITICALLY on crank. Really really look at what you have for spark.



I finally "went" EFI, but before I did, the best three things I did with an Edelbrock carb were:

Added a vapor return system, AKA WIx 33040/41 with 1/4" return port

Abandoned mechanical pump, installed rear mount electric pump

Use carb heat isolator.

Even then, on really hot stops, the car would crank for maybe 8 seconds sometimes, and would not idle smooth for a few seconds. But at least it would start, and after say, 10-15 seconds, run OK after

The EFI has completely changed all that.
 
Please describe how you added a vapor return system using AKA WIx 33040/41 with 1/4" return port fuel filter. I have this problem with my 71 RR but not with my 66 Barracuda.
Thanks 8)
 
bbeep71 said:
Please describe how you added a vapor return system using AKA WIx 33040/41 with 1/4" return port fuel filter. I have this problem with my 71 RR but not with my 66 Barracuda.
Thanks 8)
Click to expand...

The RR are more complicated because of the way the vent system works. On my 67, there is only the vent at the top of the filler pipe, and of course no "carbon can" system. So on my car, I emptied the tank, flooded the tank with CO2 from my MIG bottle, and silver-brazed a second line fitting into the front face of the tank to one side of the sender/ pickup mount. This became the return port.

I'm not sure what you'd do on your RR. You'd have to study how the present vent system works, be absolutely sure you don't cause a problem in that regard.

The Wix 33040/41 are 5/16 and 3/8" line filters, respectively, and both have a 1/4" orifice return port, which you then run back to the tank.

First time I ever saw one of these systems was used on my 6-pak RR in 70. They do work!!!
 
Guess I need to relook at that. I'm running 20 degrees initial. Seems to like it there. I've tried 5 and 10 but 20 seems to be best even with a vacuum gauge.
 
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