84 720 float issue

1980-1986 Datsun 720 forums. All 720-specific topics and discussion can be found here.
Posts: 1
Joined: Thu Mar 03, 2022 1:18 pm
Car: 1984 Datsun 720 pickup


The truck start's up, runs a while then die due to no fuel. I tracked it down to the float bowl.. it's not letting new fuel in.. I let the truck sit about 10 minutes, then the fuel is refilled.. any one had this issue? solutions?
I'm thinking there maybe a hole on the float the prevent it to rise and let new fuel in.. Your thoughts??

User avatar
Technical Expert
Posts: 7821
Joined: Thu Nov 12, 2020 1:25 pm
Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S


If the float was "sunk" you'd be flooding, not getting insufficient fuel. Needles can stick in the up position from crud or varnish, so that's a possibility but you'll need to open the bowl to find out. A clogged fuel filter will also behave that way on a vehicle with an electric pump, because most pumps have an anti-siphon valve which traps the head pressure. That keeps fuel "bleeding" through the clogged filter after the engine shuts down, so the bowl gradually refills. Some filters have anti-siphon valves as well and will cause strange fuel problems if installed backwards.

Return to “Datsun 720”