Stewart Warner 240A Fuel Pump Switch Renewal

Yes - that's the one Pedro.

 

[Randy V]

Brian I wonder if the document I just posted is the same one you have, this one has very good information or replacing the switch.

This *IS* the document I authored... I hope it is of some help!

 

[Pat]

Excellent thread now that I got my hands on a SW 240A. I’ll try and download these documents on my computer later. Sad the photos are long gone. Has anyone gotten more resources for this pumps now? Parts or manuals? Thanks.

 

[Neal]

Here you go…

 

[Mark H.]

Read the above write up by Randy V on the SW240 pump switch. I just took my 240 apart, got the pump to run fine , except will not pump much fuel, just labors, slows down under load from the fuel. Does anyone know if the switch clicks to open the circuit and remains open then clicks closed closing the circuit or should the switch perform as an immediate momentary switch .... off on off on etc...? Thinking the switch may not be cycling and activating correctly when under load as I might have assembled incorrectly . Any info appreciated. Thanks Mark

 

[Randy V]

Read the above write up by Randy V on the SW240 pump switch. I just took my 240 apart, got the pump to run fine , except will not pump much fuel, just labors, slows down under load from the fuel. Does anyone know if the switch clicks to open the circuit and remains open then clicks closed closing the circuit or should the switch perform as an immediate momentary switch .... off on off on etc...? Thinking the switch may not be cycling and activating correctly when under load as I might have assembled incorrectly . Any info appreciated. Thanks Mark

Mark - it sounds like perhaps you still have some varnish on the contacts. I recall having to use very fine emery cloth on them along with contact cleaner. I just can’t recall the exact electrical function of the switch in circuit…

 

[Mark H.]

Thanks for responding Randy. I will clean them again, has a mechanical hard closing and opening like a light switch, even when not under an electrical load. Maybe the issue is elsewhere, weak coil, piston ball not sealing? Pretty intrigue pump comparied to a rotary Holley. I see that Charlie of Gold parts has parts. Have asked him the question too.

 

[Mark H.]

Well... decided to take the SW240 fuel pump switch apart, near all the way. So to make a long story short, appears the round diaphram seal inside the lever cavity gets hard overtime and restricts the movement of the pin arm that opens and closes the points. I replaced this diaphragm and the switch opens and closes the points perfectly. It is a real tedious operation; removing the cripped case to release the pivot housing unit, then removing the .040" pivot wire hinge and machining off the pressed on diaphram retaining bushing from the point operating arm. The finger that sits in and moves with the piston groove has a small spring encapulated in its housing and rocks independently of the points operating arm. This part of the unit is roll crimped in place. Removing this spring and finger would be a major job, however with the six switches done so far this part of the unit seems pretty robust, none have shown any sign of wear. Reassembly is again tedious, pressing on a new diaphragm and bushing then recrimping the unit back into the switch housing. I got all the switches to operate and the test pump I use really pumps. Thought some might find this interesting, I sure did.