Yes, the tank is vented, and I've left the cap off and it makes no
difference. The pump can't suck fuel out of the tank on a regular basis, so
the suction creates bubbles in the pump, that's what I mean by cavitation.
I think there is some debris in the tank that partially plugs the pick up.
I have a clear filter before the pump, and it doesn't look clogged. I've
seen this once before in the '80's, when a piece of surgical tubing was
stuffed back into the tank after someone siphoned gas during the last gas
"crisis". After a few years, the thing dissolved into swollen goo particles
that clogged the pick up intermittently.
I guess 43 years is enough for a gas tank.
From: Ed Woods [mailto:email@example.com]
Sent: Friday, June 20, 2008 5:41 PM
To: Stuart MacMillan
Subject: Re: [Mgs] Fuel tank problem--ideas?
Here's a thought: Is the tank vented somewhere? It has to be y'know. If you
cannot find a vent, remove the gas cap and drive it. Does the problem go
away? If so, vent the tank by drilling a hole in your gas cap; not the
chrome cover, the part that seals the opening.
----- Original Message -----
From: "Stuart MacMillan" <firstname.lastname@example.org>
Sent: Friday, June 20, 2008 8:11 PM
Subject: [Mgs] Fuel tank problem--ideas?
> My 1965 B has given me a lot of trouble over the last couple of years.
> year it was a coil that quit when hot. Stranded me three times before I
> figured it out, after replacing everything else first. The worst was
> waiting for a drawbridge that took a half hour. I tried to wait it out by
> idling, but gave up and shut the hot engine down. Of course, it wouldn't
> start. Five miles of traffic backed up between me and the bridge. Coils
> never fail, do they? I've never seen this in my 45 years of messing with
> Now I've got a pump cavitation problem. I've tried two other pumps, and
> am using Moss's solid state pump that resists cavitation. It's pretty
> good, but not perfect. I hear a loud clicking when it cavitates, and it
> comes and goes. If it stays long enough the engine will die, but restart.
> So, the only thing I'm left with is the tank. It is the original, so I
> can't complain I guess. But, if I remove the line, gas runs out of it no
> problem. The only thing I can figure is that rust or debris is clogging
> pick up when the pump is pumping. But when I detach it from the carbs it
> seems to pump fine.
> Any other ideas? It looks like the only aftermarket tanks out there are
> without baffles, and I don't like that idea.
> '65 Roadster
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