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Carb float /fuel return line

Posted: Sun Nov 11, 2007 7:34 pm
by DL
Hi,

Carby on my chev is just the rang dang 2 barrel job. 99% of the time it is on gas. Gets only about 300 k's out of a tank of petrol and is obviously running rich. Have perfect needle and seat. Moulded foam float.

I've noticed Slunnie's thread on Aulro about the fuel return line and I've already drilled out that little hole in the fitting, which muct sit on a twin carb 3.5 closest to the tank return. Blown out the return line as well. All tank vents good, i.e. no extra pressurization. Made little difference.

Heard a long time ago that moulded foam floats don't last and will soak up petrol, thus not properly shutting off needle and seat. Is this true, and would lpg make matters worse?

Be nice to have the light grey pipe on petrol.

cheers, DL

Re: Carb float /fuel return line

Posted: Tue Nov 13, 2007 8:50 pm
by Loanrangie
DL wrote:Hi,

Carby on my chev is just the rang dang 2 barrel job. 99% of the time it is on gas. Gets only about 300 k's out of a tank of petrol and is obviously running rich. Have perfect needle and seat. Moulded foam float.

I've noticed Slunnie's thread on Aulro about the fuel return line and I've already drilled out that little hole in the fitting, which muct sit on a twin carb 3.5 closest to the tank return. Blown out the return line as well. All tank vents good, i.e. no extra pressurization. Made little difference.

Heard a long time ago that moulded foam floats don't last and will soak up petrol, thus not properly shutting off needle and seat. Is this true, and would lpg make matters worse?

Be nice to have the light grey pipe on petrol.

cheers, DL
I had a solid plastic float in my holley and that never gave any problems, i never found the need to fit the return line to the holley as it ran great as it was. When on gas there wont be any fuel in the bowl so the only reason for a different float is the old brass ones got hot and split which would then cause flooding when running on petrol again.

Posted: Tue Nov 13, 2007 10:43 pm
by DL
Thanks,

Reason I asked about foam floats is I can remember my grandfather saying to me years ago that foam floats had a prob where they deteriorate somehow and start soaking up fuel, thus not shutting off at the seat when they should. What he didn't know about mechanicals wasn't worth knowing.

He wasn't a big fan of Chevs either, even though he had a GM dealership in Minyip at one stage.

Was yours a hollow plastic float or a block of plastic foam?

cheers, DL