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Ecklers AutoMotive
Username Post: fuel evaporation?        (Topic#353737)
Posts: 32

Loc: washington state
Reg: 12-23-16
11-02-18 03:46 PM - Post#2750284    

is it possible for fuel to evaporate from the carb all the way down the fuel line to the fuel pump? new Edelbrock carburetor, new fuel lines, new filter, new fuel pump!
I start the car, let it run for a minute and shut it down and the filter shows about 1/3 full of fuel.come out the next day and there is no fuel showing in the filter. if I clamp the fuel line between the filter and the carb the filter keeps the level.

Ecklers AutoMotive
Silver Supporting Member
Posts: 7012
Loc: Nova Scotia, Canada
Reg: 08-21-01
11-03-18 05:31 AM - Post#2750322    
    In response to jrhopkins

I would say yes. Today’s fuel is very volatile , just leave it on a plate and see how quickly it disappears.

63 Pontiac Parisienne Sport Coupe(CDN Chev mechanically (409, 4 speed),62 Bel Air SC (sold), 59 El Camino (sold), 62 Bel Air SC(sold), 63 SWC Vette (sold),
Member #2194

4dr 57 
Valued Contributor
Posts: 4572
4dr 57
Loc: Texas Hill Country
Reg: 11-10-04
11-04-18 03:43 AM - Post#2750392    
    In response to DonSSDD

Although my application is different the problem is the same, hence my desire to lose the stock fuel pump (with return line.) The plan seems to center around a carb regulator from Summit and an inline fuel pump.
The easiest approach seems to be to mount the regulator in place of the fuel pump where I will hopefully only need to make a new line to the carburator. Of course the fuel line will need spliced and flared as well. Worth it imho!

It's all good. mostly

"9th Year" Silver Supporting Member
Posts: 338
Loc: Chicago
Reg: 01-03-13
11-05-18 11:58 AM - Post#2750516    
    In response to jrhopkins

Just guessing theoretically here, but maybe its not evaporating all the way down to the fuel pump, but just draining down. And maybe this is "normal". Check valve(s) in the fuel pump probably do not seal absolutely, a little seep-thru would let fuel in the line slowly seek its own level with fuel in the tank. When you clamped the line near the carb, vacuum above the fuel in the line kept it from draining down.

And I don't think you need fuel standing in the line all the way to carb; engine starts with fuel in the carb's float bowl. Within just a couple seconds of cranking the fuel pump would push air out of the line and have fuel up to the carb.

Ecklers AutoMotive
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