Lift pump not Lifting? FL 120

Caribe · 04-23-2013, 10:43 AM

Hello! I just changed primary and secondary filters and primed new ones Port engine went great but when bleeding my starboard, the lift pump was not pumping fuel. The lever moves fine but there is no fuel moving. I took off cover and cleaned. The diaphram is old but not too bad looking...I looked back through old posts that made me think there might be something I'm missing....any ideas?? THANK YOU!!!!

Daddyo · 04-23-2013, 11:07 AM

Time to replace or rebuild me thinks.

Marin · 04-23-2013, 11:20 AM

The stock lift pump on the FL120 cannot be rebuilt, according to American Diesel, because the rebuild kits are no longer available. However, brand new pumps are available. This was the case several years ago when I wanted to buy a pair of rebuild kits to have on the boat. It would be worth checking with AD to see if rebuild kits are still not available.

If the pump does not move fuel with the manual lever the usual reason is that the lever drive arm is being held in the wrong position on the camshaft. So the engine needs to be "bumped" with the starter to put the arm in the correct position to allow the manual lever to move the diaphragm.

If you did this and it is still not moving fuel then the pump itself has a problem although I can't think what it would be if the diaphragm is okay. They are pretty simple devices.

mahal · 04-23-2013, 11:21 AM

Things I would do in your situation: make sure I reopened the fuel shut-off valve, check that I didn't create an ail leak when replacing the primaries and that its air relief valve is closed while pumping the lift pump. I'd also turn the engine (without starting) and try pumping again. If still no luck, I'd install my spare lift pump.

**FlyWright** · 04-23-2013, 11:47 AM

I don't know that engine, but on my Perkins, when I bleed the lift pump, I first bleed from the engine mounted fuel filter top until it's full, then at the high pressure fuel pump until that line is purged of air. Could it be that you have air in the line upstream from the lift pump or a supply line blockage/fuel valve turned off on that side?

Caribe · 04-23-2013, 05:18 PM

Bumped starter - finally got lever working...got a lot of air in lines. Bled filters injector pump and injectors and it's purring like a kitten...after 30 years she's likely a cat...thank you!!!