My experience is that low pressure electric pumps still are too high a pressure
for SUs. The old Pierburg OEM pump is mighty hard to beat and they are still
making them. Not to argue with Rhys, but I have been using filters on both
sides of the pump and not had any problems related to them except when they
get plugged. I am careful to locate them where they don't get too hot,
typically near the oil filler, like yours.

It sounds to me like your float valve may not be closing right. Might be
good to clean it with a Q-tip and make sure that it is screwed in good and
tight with the black fiber ring under it. A 5/16"/8mm or 11/32" socket
works pretty well depending on which size it is.

If you can get by with doing so in your locality, you might consider using
the canister/tubes etc as a donation for the trash. (This probably won't
play in 'fornia.)
--
George Downs, Bartlesville, Oklahoma, Central US