Stewart-Warner 240A fuel pump question

Jim Rosenthal

Supporter
We are having trouble with the pumps in 1149, which lose prime as soon as you shut them off, and then won't reprime. The pumps run in parallel, drawing through a Spitfire selector valve from the two tanks. The pump outputs are then merged to go into a single fuel line, to the filter/regulator unit, which has a glass bowl, and from there to the Weber carbs. When you shut the pumps down, you can see the fuel filter bowl drain immediately.

I don't recall this happening before. Does anyone know enough about 240A pumps, which haven't been made since I think the 70s, to know if they have an anti-drainback feature in them? this is maddening.
 
We are having trouble with the pumps in 1149, which lose prime as soon as you shut them off, and then won't reprime. The pumps run in parallel, drawing through a Spitfire selector valve from the two tanks. The pump outputs are then merged to go into a single fuel line, to the filter/regulator unit, which has a glass bowl, and from there to the Weber carbs. When you shut the pumps down, you can see the fuel filter bowl drain immediately.

I don't recall this happening before. Does anyone know enough about 240A pumps, which haven't been made since I think the 70s, to know if they have an anti-drainback feature in them? this is maddening.
Possibly an air leak on the suction side? Seen that happen on race cars with braided AN hose
 

Brian Stewart
Yes, I would suspect an air leak Jim. I run two 240As and, while the lines gradually empty after shut-off, the pumps prime up and fill the filter/lines within 2-3 seconds when switched back on.
 

Jim Rosenthal

Supporter
Air leak on the suction side.... that makes sense, because an air leak on the pressure side would leak fuel... I'll see if I can find that..
 
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