Lehman 120 Lift Pump

Hello smart people. I've been a lurker but now I need more brain power.

I'm replacing the lift pump on a FL120 on a MT single engine. The location of the lift pump makes accessing the two nuts to remove it a PITA, but I managed to get the old pump off. Off-set wrench and a grinder modify the wrench was the trick.

Now I cannot for the life of me figure out how to get the pump lift arm on the new pump into the engine block in such a manner that I properly place it against the cam and still have the two mounting holes lined up to slide the pump on. I've tried "bumping" the engine to change to cam lobe position, but still no go.

When the lift pump arm is in the engine block, the pump seems cocked to one side and the holes won't line up. Is there some sort of trick to this or do I just need to keep fighting it and cussing?

Thanks in advance!

I would take a 15/16 wrench on the crank pulley and bar the engine over by hand. "Bumping" it may be moving the cam into the same place each time.

I like this idea. Every time I "bumped" I wondered if I was just doing exactly what you suggest. Thanks

Good advice. The cam needs to be in a position such that you can slide it in with ease. It's not a choice many boaters would make but I eliminated the mechanical pump and installed a Walbro electric pump. A big block Chevy fuel pump block-off plate is an exact replacement for the pump mating surface. Plus, that surface is known to sometimes leak with the mechanical pump in place.

SoWhat said:

I would take a 15/16 wrench on the crank pulley and bar the engine over by hand. "Bumping" it may be moving the cam into the same place each time.

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Thanks Catalinajack. I may look into that as an upgrade based on the struggle to get the mechanical pump out this time. What model Walbro did you use and how did you integrate it into the electrical system?

I'm excited to report back that using this method allowed me to align and mount the pump with little difficulty. Thank You both!

...but the engine won't start now. I bled the system at the top of the dual fuel filters on the engine prior to cranking but now is just sounds like it doesn't even want to think about firing as it cranks. I only gave it three good tries before I quit for the day in fear of causing a hydrolock or killing my starting batteries.

Ideas anyone?

Almost any 12v fuel pump (rated for diesel) will work to replace the lift pump. About $20 on eBay. Buy 2, they're cheap and then you a spare. I have twin Detroits and 2 generators. Each has an electric in line with the lift pump for filter changes and bleeding (on the generators). Plumbed directly inline, the stock pump pulls thru the electric. Should it fail, all I have to do is flip a switch. When the Onan and Perkins lift pumps eventually fail, I'll go all electric.

You are only half way there on the bleeding. You also have these two little guys - the one above the word MINIMEC and the one above the word ENGLAND

Here is where my bleed screws are located. Pump until the aft one no longer has air coming out. Tighten it down then open the forward screw and repeat.

I have SP225s and have never had to bleed the injection pump. I just change the filters and bleed them then the engines start right up. Is mine different or have I just been lucky?

Thanks for the bleeding advice. I will try that this afternoon.

As I was looking around on the 'net I did read that the turbocharged engines do not require the injector pumps to be bled as they are self-purging (Comodave)

Also be careful when you tighten the bleed screws up. The housing is aluminum and it wouldn't take much force to damage the threads.

Comodave said:

I have SP225s and have never had to bleed the injection pump. I just change the filters and bleed them then the engines start right up. Is mine different or have I just been lucky?

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Same here.......So far.

Fuel level high enough might be the answer to no bleeding....

Replaced mine with a Whalbro FRB-9. Remove the mechanical pump or you risk blowing the pump diaphragm and filling the engine with fuel.

The mechanics will cringe in despair but in a desperate situation crack open an injector and crank until it starts. Not the proper way!! But if you’re in a channel with no place to anchor and drifting into the rocks...

psneeld said:

Fuel level high enough might be the answer to no bleeding....

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The Raycor’s are lower than the tanks so they fill on their own. I filled the two secondary’s with a bottle, screwed them on, and started the motor with the bleed valves open. Trying to fill the secondary’s with the hand lever on the pump is comical. This was first time for me. See what happens next time around.

SeaMoose said:

Replaced mine with a Whalbro FRB-9. Remove the mechanical pump or you risk blowing the pump diaphragm and filling the engine with fuel.

The mechanics will cringe in despair but in a desperate situation crack open an injector and crank until it starts. Not the proper way!! But if you’re in a channel with no place to anchor and drifting into the rocks...

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No need on the 120. The two posts showing the bleeds on the inj pump are the answer. I always just used the forward one only, and it took very little cranking. Remember to close the cooling water through hull if you are cranking a bunch with no start.

I never had a problem using the lift pump lever to prime but I have an electric fuel pump plumbed as a backup if needed and to assist in bleeding.

Never used either lift pump lever on my 120s because cracking the the inj pump bleed ALWAYS work with just seconds of cranking.

So the answer was the bleeding on the injector pump. Bled the forward location, then cracked open all 6 injector lines and cranked for about 15 seconds, twice. On the second 15 second crank I had fuel from all the injector ports. Secured the fittings again and the engine fired right up.

Thanks to all for the help. I am still considering the electric option at least to have on board in the event of "next time"

BradC said:

So the answer was the bleeding on the injector pump. Bled the forward location, then cracked open all 6 injector lines and cranked for about 15 seconds, twice. On the second 15 second crank I had fuel from all the injector ports. Secured the fittings again and the engine fired right up.

Thanks to all for the help. I am still considering the electric option at least to have on board in the event of "next time"

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Did you even try the 2 bleeder ports on the injection pump that are in the above pictures?

You probably would have had the same results without cracking the injector nuts. Bleeding the pump should be sufficient. I know it is on mine.

The pump on mine only has one bleeder nut, located forward. I opened that first and cranked a few times and did get some air and then fuel. Closed that nut and no joy on the attempt to start, so just cracked all 6 injector lines, did the two 15 second cranks and got fuel from all six on the second crank. Closed them down and the engine now purrs like always.

You have a Lehman 120 and what kind of fuel injection pump?

I grabbed this picture from another thread, so it's not my actual pump, but it is exactly like my pump.

thanks, haven't seen one like that.


hard to believe the one isn't good enough as the 2 on most seem to be a waste as the forward one seems to bleed the pump just fine.

The electric also aids in the priming process...pump on until that forward filter fills up...a little late but ..I have twin 80 Lehman’s and taking off the oil filter mount allowed me access to the lift pump screws and a bent 1/2 wrench was a life saver for re and re.