Walbro FRB20 Fuel Pump

[eugenesdream]

Hey everyone, I just installed a Walbro FRB20 electrical fuel pump on my Yanmar 2GM. Replacing the original Walbro 6095 pump that seemed to not be working anymore.

I was able to bleed the fuel lines after a ton of effort to get her running with the new pump installed. However, she eventually stalled out as fuel seems to be moving too slow through the system. The pump is supposed to sense when fuel is needed and deliver at appropriate pressure and rate. Yet it really seems to barely be pumping much fuel at all.

Upon testing the pump disconnected from the engine it is a minor spit of fuel that is pumped out every 5-6 seconds. So it is no surprise it takes forever for fuel just to get to the first bleed nut and eventually be able to get air out of the system, then start her up. But it does not seem to be a strong enough flow of fuel eventually leading to the engine stalling. I am coming to this conclusion as after stalling the fuel lines on the engine are essentially empty and it takes forever to see fuel at the bleed nuts again.

My fuel system goes: Fuel Tank - Racor 500FG - Walbro FRB20 fuel pump - Engine. The engine does still have the manual fuel pump on it.

The reason the electric fuel pump is necessary is because the tank is so far away (6+ feet) and the level of rise is a solid few feet (~4).

So my question is did I buy the wrong fuel pump? Maybe I should have something with a higher flow rate / pressure to consistently feed fuel to the engine. This current one does not seem to be doing the trick. The Walbro FRB20 minimum flow rate is apparently 125 liters per hour (33 gph). I highly doubt it is doing that though.

Any advice or similar stories is appreciated.

[gamayun]

When I went to the Walbro website, it gave me an error message trying to link to the FRB-20 specs. Is this a new pump? I just installed the FRB-13 with a Raycor on my Yanmar 3GM30F. I still have the Yanmar fuel pump on the engine but it's a pain to use. I used the Walbro instead to bleed the engine (first time everything got back online today!) and it worked great, but then the pump gets powered off. It doesn't need to remain running for the fuel to go through so you might have another issue going on. I think the pressure on the FRB-13 is 6-8 psi. In fact, that was a whole lot more pressure than I was expecting as the fuel squirted like crazy from the bleed screw. Did you prime the Raycor first? I don't know whether these pumps can run dry, but the first time around, I used an old (Walbro type) fuel pump and it gave up the ghost trying to pull the fuel from the tank with the Raycor bowl empty. Not sure any of this helps. Just giving you my experience in case it might trigger a light bulb moment. Good luck!

[sailormed]

Try the pump connected directly to the battery. Seems it is a voltage problem you have.

[skipperpete]

It seems that you might have a suction line blockage, maybe try putting the pump inet line in a can of clean fuel and see if it delivers a better flow.
There is a chance that the mechanical lift pump has a blockage or a stuck valve too.
Pete.

[tkeithlu]

Two liters a minute is a whopping flow. Have you checked the Rancor and everything else on the suction side for a blockage? You should have very clear flow getting to the pump, and it sounds like it is starved.

[eugenesdream]

Originally Posted by gamayun

When I went to the Walbro website, it gave me an error message trying to link to the FRB-20 specs. Is this a new pump? I just installed the FRB-13 with a Raycor on my Yanmar 3GM30F. I still have the Yanmar fuel pump on the engine but it's a pain to use. I used the Walbro instead to bleed the engine (first time everything got back online today!) and it worked great, but then the pump gets powered off. It doesn't need to remain running for the fuel to go through so you might have another issue going on.

You can find the specs for the FRB20 here:
https://walbrofuelpumps.com/frb-20.html

I think SkipperPete is right and there is a suction side blockage. I have an inline primer bulb before the Racor from the gas tank. I noticed it is sucking in and not easily inflating again. Definitely caused by suction. So I'm assuming gas is not flowing nicely out of the tank. I dropped bio treatment in the tank not long ago so I doubt it is growth. It may just be that old primer bulb creating a vacuum or clog in the line.

I'm going to run the fuel pump directly to the fuel tank line and see how it flows. Remove the hand pump from the suction side, and take it from there. Should be able to sort it out from there. I assume the primer bulb shouldn't be on the suction side anyway. Not sure why it was put there.

[MAJICDAN]

Check the inlet screen inside the inlet port of the pump

[sophiedaisey]

Sounds like you could have a air leak between the tank and the Pump. You no longer need the primer bulb before the Racor. Personally I would remove it. Have to have a leak free system before get good fuel flow. You may ask how I know🤪

[eugenesdream]

Just want to let everyone in this thread know I figured out the issue and have been sailing again. Engine is back to being reliable and running great.

However I have noticed the old manual fuel pump is definitely on it's way out. Probably can't handle the pressure being pumped in from the new electric fuel pump. The gasket in the middle of the pump body is getting wet and I know a fuel leak is inevitable. So I am going to just replace it.

Has anyone done a Yanmar manual fuel pump replacement? Any advice is appreciated. Seems fairly straightforward, but I'll take any help I can get.

[Wotname]

Originally Posted by eugenesdream

.........
Has anyone done a Yanmar manual fuel pump replacement? Any advice is appreciated. Seems fairly straightforward, but I'll take any help I can get.

Very straightforward. I guess anything can be messed up but it hard to see how this job could go wrong.

A picture tells a thousand words so...

[sophiedaisey]

Great news. What was the problem?
Regarding new manual life pump, agree with above post. If I can do it then anyone can.

[eugenesdream]

Originally Posted by sophiedaisey

Great news. What was the problem?
Regarding new manual life pump, agree with above post. If I can do it then anyone can.

It was definitely that old primer bulb before the Racor creating a vacuum and stopping the flow of fuel. I removed it, noticed an immediate change in the electric fuel pump when bleeding the system, and she has run like a champ during my last few sails.

Purchasing the manual fuel pump replacement today. Not too worried about doing the job, but was concerned maybe the lever had to meet the cam inside the engine in a certain way or something. But I'm sure I'll be fine. After rewiring the whole boat, rebuilding the fuel system, and all the various engine work I've done I'm confident enough nowadays.

Thank you Wotname for the documentation! I should have looked for that right away!!