For a 4 foot lift and a Yanmar 2GM20F engine, What Walbro electric fuel pump model do you recommend? The original was a Walbro WEP-12. Some have used a Walbro 6805, which is no longer made. We are about to replace the Racor 120 with a Racor 500 MA 10-micron fuel filter. There is strong evidence that previous owners have had air in the fuel issues (2 micron primary filter, outboard motor primer bulb at tank outlet (not USCG approved), stripped threads on bleed screw of secondary fuel filter, hose size too large for barb, failed electric fuel pumps, etc.). Both the fuel supply and return from the aft most injector have a high point of 4 feet from the bottom of the tank. I am thinking of replumbing the fuel hoses to eliminate the high point. The tank is 2 feet tall so the head or lift is 2 feet with a full tank. Fuel consumption is approx. 0.4 gph so the Racor 500 MA is over kill, but easy for filter changes with a pressure gauge on the pump's suction side. What is the maximum pressure for the low pressure side of the 2GM20F? I'm thinking of either the FRA 2 or FRA 20, but confused about running continuously (FRA 2) or when fuel is demanded (FRB 20). Thoughts? Thanks.
Electric Fuel Pump Replacement Yanmar 2GM20F
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Origional ???
You stated that the origional was a WEP12. I think that all the GM series Yanmars came with a mechanical lift pump, and as far as I know there were never any of them equipped with an electric pump. The pump you have is an optional add on, and not required for the engine to perform, unless there is something wrong with the mechanical lift pump. I do prefer having an electric insalled, but I have always had the electric switched, and left turned off unless needed. They are great for bleeding the system, checking the suction side for leaks, etc. As far as I know all those pumps are internally regulated for pressure, and the lift you describe should not be a problem with any of them. So, just go with what you feel comfortable with.
You stated that the origional was a WEP12. I think that all the GM series Yanmars came with a mechanical lift pump, and as far as I know there were never any of them equipped with an electric pump. The pump you have is an optional add on, and not required for the engine to perform, unless there is something wrong with the mechanical lift pump. I do prefer having an electric insalled, but I have always had the electric switched, and left turned off unless needed. They are great for bleeding the system, checking the suction side for leaks, etc. As far as I know all those pumps are internally regulated for pressure, and the lift you describe should not be a problem with any of them. So, just go with what you feel comfortable with.
The electric is an option.There is a mechanical pump.
I installed an electrical as a back-up and for bleeding purposes.
Check to see if the mechanical one has been removed before proceeding.
Easy to check.
Good luck
I installed an electrical as a back-up and for bleeding purposes.
Check to see if the mechanical one has been removed before proceeding.
Easy to check.
Good luck
To be able to tell you the model I would have to go down to the boat and actually look at it, sorry.
Mine is not switched, if the power is on so is the pump.
Mine is not switched, if the power is on so is the pump.
The fuel tank on s/v Mosaic is in the keel. The Yanmar 2GM20F engine mechanical lift pump is sufficient to raise fuel 0.8 meters or 31.5 inches. There is a typo in our Yanmar Service Manual showing 3.15 inches. The Yanmar Manual shows a suction pressure -60 mm Hg (mercury) or 1.16 psi or 32-inches of water (close enough considering the difference in specific gravity). Note that the 31.5-inch lift capacity is a straight lift and does not include fuel hose bends, any 90-degree fittings, micron rating or clogged condition of primary filter, etc., which will increase the lift required. Theoretically, for pumps in series, the pressures are additive so one would not want an auxiliary electric fuel pump with too high a pressure to keep the cumulative pressure low (according to Rich ~ s/vTayana, less than 15 psi, which provides a factor of safety of 2 if RACOR's max. pressure rating is 30 psi). S/V Mosaic's pump is keyed to the ignition and runs continuously when the motor runs. Any extra fuel at the aft most injector is plumbed back to the fuel tank - sort of like continuous fuel polishing. We will probably pull the fuel through the Racor 500, will use a vacuum gauge on the suction side of the RACOR, change out yearly or 6" of Hg (whichever comes first). So now lets size the pump requirements: 6" of Hg equals 3 psi. This is greater than the mechanical lift pump capacity of 1.16 psi. The difference is 3 - 1.16 = 1.84 psi. So we need a booster pump with an additional capacity of 1.84 psi. The shutoff pressure of the Walbro FRA-2 ranges from 2.30 low to 4.08 psi high with an average shutoff at 3.58 psi. So FRA-2 is okay 2.30 is greater that 1.84 psi and since it runs continuously all we need to do is watch the vacuum gauge and change the filter at 6" of Hg or yearly whichever comes first. A higher pressure rated pump like the FRB-13 at 6-8 psi will also be satisfactory. Hope this helps understand pumps in series, pump pressure/lift capicity.
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