[Public-List] A4 fuel problem

[Daniel Sternglass]

Gord,

The most likely cause seems to me to be that the float valve is getting 
stuck. This seems likely since it takes a lot of cranking to re-start 
when when you switch back to the good tank. A frequent cause of this is 
squirting carburetor cleaner into the carb -- the float valve has a tiny 
rubber tip, which is softened by the cleaner. If you haven't replaced 
the float valve in a long time, it may have been softened by ethanol. 
It's an easy job, but you will nee a new carburetor body gasket. You can 
check if there's gas in the float bowl via a drain plug. Try rapping on 
the top of the float bowl with and see if it starts, that is often a 
giveaway for this problem.

Assuming that you have an electric fuel pump, you may want to do what I 
did to make it easy to solve fuel system problems. I wired a switch in 
parallel with the oil pressure switch that is (supposed) to be wired in 
series with the pump to stop the fuel pump from running if the engine stops.

One way or the other, if you have a switch to run the pump "manually", 
you can disconnect the fuel line at the carb and see if a strong stream 
of fuel is getting to the carb with the plumbing switched to either 
tank. You can also use that to pump the tank (pretty much) dry at the 
end of the season. Earlier this year, using that switch let me track 
down a plugged filter.

Hope this helps,

--Dan Sternglass
Watcher of the Skies, #201, 1966, Cayuga Lake, Ithaca, NY

-- 
dans at stmktg.com
mobile: +1607-592-8012

Strategic Marketing Associates
403 Highgate Road
Ithaca, NY 14850