70vert

Any body else ever have fuel percoation problems in the carburetor? I have rebuilt the carb, new float, needle and seat, new steel fuel line from pump to carb. I still get percolation, fuel running out of the acc. pump, fuel percolating in the primaries. At this point I figure it is not a carb problem but a hot fuel problem. BTW this is a 70 BB. Next fix I will try the following: insulate the fuel line between carb and pump, phenolic spacer between intake and carb (if room allows), new fuel pump (pump is stock, maybe the return side is blocked, letting hot fuel to the carb??), test the return line for blockage, and finnally I plan on taking the fuel tank out to inspect and seal if neccessary.
Has anyone insulated their fuel line? What material did you use? Anybody ever use a phenolic spacer? Whick one, the 4-hole or the single square hole? Any interferance problems with the 1" spacer? Any other sugestions?
I am really getting sick of being stranded on the roadside (plus it is unsettling to have fuel on the hot intake). This has happened 4 times now, always when hot; the time between the last two intervals was approx. 200 miles which consisted of several up-to-temperature short trips.
Please help and thanks in advance.

Matt Gruber

usually it happens after a hot soak(off for 10-20 minutes)
yours is driving down the road?

bigvette1

Two things on this

1. Insulated gasket being used?
2. Fuel line touching the head picking up heat?

Alwyn678

I did until I put a wood carb spacer on the car......Now it is not a problem

70vert

This happens when I'm going down the road, engine will just die, open the hood-gas pooled on the intake and bubbling (also in the primaries).
I have the gasket that's about 3/16" thick that came with the kit between the carb and intake, the fuel line touches nothing except the carb on one end and the pump on the other (stock set-up).
Where can I get the wood spacer?

BSeery

phenolic spacer - wood spacer --- darn near the same thing.

Surfer69

I have problem with heat soak also and accelerator pump. Lars said alchohol in gasoline can cause lower boiling of fuel. I havent checked to see if purcolating but get sputtering on quick acceleration attemps. He said try alchohol resistant a-pump, heat sheild or bumping jets one size up. My .02

Matt Gruber

i had that exact same problem in 1970, on a 66 chevelle vert w/ a qjet. It happened several times and i am amazed it never caught fire.
I wish i knew lars back then.
That is
FLOODING
not
PERCOLATION
aT THE TIME THE CAUSE ESCAPED ME!
i sold the car, i checked/ changed te needle/seat. Might of been a float going bad? see lars' articles

Alwyn678

Both make good insulators
http://cgi.aol.ebay.com/ebaymotors/w...category=33551

Matt Gruber

lars?

Brettmc

I think it's prolly a pressure problem. Check to make sure the vented cap works and the return line is ok. I had a similar problem with mine. It would sputter and die while driving. I'd take the air cleaner off and fuel would be comin out the vent & pump shooters. It turns out that I had put a nonvented gas cap on it and plugged up the return line in trying to get rid of a gas smell while parked in the garage. Once I put a vented cap back on it, all was well.

Brett :thumbs:


[Modified by Brettmc, 9:51 AM 7/8/2003]

bigvette1

I will agree with the last post by Brettmc. Pressure or carb parts/adjustments especially with the float needle and seat. I would take apart the carb, make sure the proper float as quoted from Lars papers on rebuilding is installed - believe from Napa. I also think the "window seats housings" can cause spill over. Good luck but get it fixed, this is a dangerous problem.