79 Volvo misses

I have a '79 240 that runs great until it has less than a half a tank o
gas. After that it will it will miss or "chug" during acceleration. Fil
it back up and it runs fine. I also always smell gas after driving
couple of miles but I can't find any leaks. Any ideas

 

Either the pre-pump has failed, or the hose that connects it to the siphon
tube has disintegrated. If you look under the carpet in the trunk there's a
cover you can remove, under it there's hoses going into the top of the fuel
tank and a cover secured by a bung nut. Get under the car and disconnect the
coupling in the fuel line and then remove the bung nut and pull the pump and
sender assembly out of the tank, I recommend replacing the rubber coupling
with a piece of new fuel hose regardless so you won't have to think about it
again. Wash the pump out with water, blow it dry and then connect it to
power (6v lantern battery will do) it should start reliably, if it has any
trouble, replace it.

 

Couple of additions: You can actually hear a running pre-pump by
putting your ear against the fuel filler tube (cap off, of course). In
my climate, the top of the sender rusts and the pipes will be very
thin. All the connections will be rusty, and when you put a little
force on them, then the pipes break and your car isn't going anywhere
until you get a new sender unit.

--
Mike F.
Thornhill (near Toronto), Ont.

Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)