Onan 7.5 KV MDJE Transfer Pump

[CapeBob]

The transfer pump in my about 1978 7.5 KW MDJE gen set is seeping a little fuel. I understand that the pumps are no longer available, but I wondering if there is a rebuild kit available or perhaps someone who can make the gaskets and diaphragms.

Thanks,
Bob

 

[Ski in NC]

Snug up the screws around diaphragm. If no joy, replace it with an electric pump. 5psi universal from auto parts store will do the job. Cut a blank of plate out of aluminum to seal off hole in block.

 

[Lepke]

The electric pump will also make it easier to bleed the injector pump and when you change the secondary filter.

 

[CapeBob]

Thanks guys.

 

[CapeBob]

It looks like I'm getting an electric pump to replace my leaking pump. Does anyone have a brand name or part number to get me started?

Thanks,
Bob

 

[CapeBob]

I found this pump online. Could this possibly be enough pump. It's only $15.

Glarks Universal 12V Low Pressure Gas Gasoline & Diesel Inline Electric Fuel Pump (Model:HEP-02A)

Bob

 

[ksanders]

I've had great luck using the Holley electric pumps. Very reliable.

 

[CapeBob]

Thanks Kevin.
Bob

 

[Gulfstar]

Hi All I too have lost the use of my transfer pump and am trying to understand the switch to an electric pump. Is this a matter of removing the existing unit and sediment bowl, blocking off the block opening and replacing with a inexpensive electric pump? How do I wire the new pump? Anybody have pictures?

 

[ksanders]

Hi All I too have lost the use of my transfer pump and am trying to understand the switch to an electric pump. Is this a matter of removing the existing unit and sediment bowl, blocking off the block opening and replacing with a inexpensive electric pump? How do I wire the new pump? Anybody have pictures?

No photos, and it has been a long time....

The idea is that you bypass the mechanical pump.
The energy for the electric pump comes from the 12 volt circuit that is energized when the engine is running. Using a relay to power the pump is a good idea.

Cover the “hole” in the block and you are good to go. Temporarially there is no reason to even remove the mechanical fuel pump, but that would be a very temporary “get the generator running” thing while you are sourcing a plate to fit the block.

 

[Gulfstar]

Thanks Ksanders Could you recommend a pump and relay?

 

[Ski in NC]

I've used a Facet 5psi pump, can be found at auto parts stores or on line. I did not use a relay, just tied + lead to fuel solenoid. Nice to add a switch to energize pump with engine off to prime, but not really needed. Can just use a jumper lead to prime.

 

[Xsbank]

Summit Racing has lots.

 

[Lepke]

I buy my electric pumps on eBay, usually about $20. Make sure it's rated for the fuel type.

 

[Gulfstar]

Thanks guys I ordered on off ebay and started to make the cover plate.

 

[Gulfstar]

Okay now the wiring question. The stop solenoid is a Prestolite with one terminal IGN and the other SW and I think the mount is the ground. What terminals should I use?

 

[ksanders]

Okay now the wiring question. The stop solenoid is a Prestolite with one terminal IGN and the other SW and I think the mount is the ground. What terminals should I use?

I do not remember. It’s been a LONG time.

Thinking about the circuit one of the terminals is energized to pull the solenoid back, and the other is to keep it back.

Ski???