Yanmar 2GM20 Lift Pump - Help!

[Wotname]

Does anyone know a part number or a source for the diaphragm and / or valves for a Yanmar 2GM20 lift pump?

Yanmar does not list parts for this pump, you have to buy a complete pump.

It appears the pump is made by Mikuni Kogyo but as they make a zillion pumps and carbies for small engines, google hasn't been that helpful is locating the Yanmar unit.

I would far rather repair then replace but withouts parts, it is difficult…

I haven't found anything on CF but this thread suggests parts might be available http://www.cruisersforum.com/forums/...p-66848-2.html

[Emmalina]

In the modern world they just want to sell you a new one ! I generally rebuild things and make the parts myself. Most raw material is available in motor spares stores.

[model 10]

In a pinch, make your own. It's nothing more than a piece of neoprene sheet with a rivet in the middle or go to an electric backup.

[Wotname]

Originally Posted by Guy

In a pinch, make your own. It's nothing more than a piece of neoprene sheet with a rivet in the middle or go to an electric backup.

Yep, might be the only option but meanwhile I hoping for a CF miracle!

[svJasmine]

Ask depco pump.

[tdh1849]

Suggestion, but call "Complete Yacht Service" the Yanmar dealer in Ft.Lauderdale and speak to Mark ( USMC) , tell him Pat N now in Tampa told you to call.
He knows all there is to know about Yanmars and pumps.................

[Sailorman Ed]

go to an electric backup.

I like the small reliable Facet pumps. What kind of pressure and flow rate would be appropriate for the 2GM20? Facet makes quite a variety.
As an added bonus, an electric pump makes bleeding the fuel system much easier.

[GrahamHO]

Originally Posted by Wotname

Does anyone know a part number or a source for the diaphragm and / or valves for a Yanmar 2GM20 lift pump?

Yanmar does not list parts for this pump, you have to buy a complete pump.

It appears the pump is made by Mikuni Kogyo but as they make a zillion pumps and carbies for small engines, google hasn't been that helpful is locating the Yanmar unit.

I would far rather repair then replace but withouts parts, it is difficult…

I haven't found anything on CF but this thread suggests parts might be available http://www.cruisersforum.com/forums/...p-66848-2.html

I replaced my 2GM20 lift pump 2 or 3 years ago. There were no spare parts listed by our NZ agents who source what they don't already carry, from Australia. From memory it cost something like NZ$150. It is such a simple pump that it's probably uneconomic to carry the individual bits.
I considered replacing it with an electric pump which I think is a good idea in principle. That would have meant new fuel lines to the electric pump and from it (or the primary filter) to the engine mounted filter. As the existing Yanmar pump to filter and filter to injection pump lines are metal (steel I guess) it was quicker and easier to drop in a new mechanical Yanmar pump. Takes about 15 minutes including a coffee break. I quickly forgot having to spend $150 or whatever it was.

[GrahamHO]

One more thing about the Yanmar pump. The $150 cost is likely $50 for the pump and $100 for the box with "Yanmar" written on it.

[01kiwijohn]

Try a local John Deere Dealer, JD uses a lot of small Yanmars in their commercial mowing and compact utility tractors.
If you decide to go electric, you could hook that into the tank supply line and just pump it through the Yanmar priming pump; that way, no need to change a lot of special, steel, fuel lines.
If you do rebuild that pump, remember to loosely assemble it, then hold the lever at it's maximum stroke position before tightening the screws that hold it together. That way, the diaphragm will not be under stress and will last much longer.

[model 10]

I used to have an old airplane with diaphragm fuel pump. Almost everything was out of production, including the fuel pump. You can't just throw an electric pump on an airplane without the FAA wanting endless engineering so you really need that new diaphragm. Somebody somewhere figured out that the diaphragm from a 60 something Chevy Corvair fuel pump fits a 1946 Bellanca Cruisair with a 150hp Franklin engine.
Somewhere there is a diaphragm for your pump but a side note, I've found the check valves in that kind of pump fail as often as the diaphragm so maybe a complete pump is a safer backup that just some of the parts.

[GrahamHO]

Originally Posted by 01kiwijohn

Try a local John Deere Dealer, JD uses a lot of small Yanmars in their commercial mowing and compact utility tractors.
If you decide to go electric, you could hook that into the tank supply line and just pump it through the Yanmar priming pump; that way, no need to change a lot of special, steel, fuel lines.
If you do rebuild that pump, remember to loosely assemble it, then hold the lever at it's maximum stroke position before tightening the screws that hold it together. That way, the diaphragm will not be under stress and will last much longer.

It is quite OK and good to run an electric pump through a mechanical one. That helps with priming. My Yanmar mechanical pump that I replaced was leaking and whatever I tried couldn't fix it so electric through mechanical would have been no use or worse. Also the Achilles Heel of the mechanical pump is if the diaphragm leaks, diesel goes into the engine oil. An electric pump before the mechanical pump would probably force more to go in.

Nothing wrong with that idea if the mechanical pump is in good order but then the need doesn't arise.

[Wotname]

Originally Posted by Sailorman Ed

I like the small reliable Facet pumps. What kind of pressure and flow rate would be appropriate for the 2GM20? Facet makes quite a variety.
As an added bonus, an electric pump makes bleeding the fuel system much easier.

Not much pressure, head it about 1 foot, lift depends on tank location but mine is somewhere between 0 and +1 foot as the tank is a gavity feed when full. Not sure about flow rate when running but it moves 3 ml per stroke of the hand lever.

Assuming cam lever moves the same amount and flow is directly proportional to engine speed, the flow rate must be 3 times 1700 ml per minute when engine is running at max continious 3400 RPM. That is 5.1 LPM or 306 LPH, roughly 60 GPH. Now this seems a little high for such a baby sized pump so perhaps my assumptions above are incorrect. Even at a tenth of this figure, ie 6 GPH it would be ample as engine is using less than half a gallon per hour at 3400RPM.

Originally Posted by GrahamHO

I replaced my 2GM20 lift pump 2 or 3 years ago. There were no spare parts listed by our NZ agents who source what they don't already carry, from Australia. From memory it cost something like NZ$150. It is such a simple pump that it's probably uneconomic to carry the individual bits.
I considered replacing it with an electric pump which I think is a good idea in principle. That would have meant new fuel lines to the electric pump and from it (or the primary filter) to the engine mounted filter. As the existing Yanmar pump to filter and filter to injection pump lines are metal (steel I guess) it was quicker and easier to drop in a new mechanical Yanmar pump. Takes about 15 minutes including a coffee break. I quickly forgot having to spend $150 or whatever it was.

Yes, currently $167 Aussie for the new pump.
Interestingly my 2GM20 has all rubber fuel lines right up to the IP. Been that way since new 2003.

Originally Posted by GrahamHO

It is quite OK and good to run an electric pump through a mechanical one. That helps with priming. My Yanmar mechanical pump that I replaced was leaking and whatever I tried couldn't fix it so electric through mechanical would have been no use or worse. Also the Achilles Heel of the mechanical pump is if the diaphragm leaks, diesel goes into the engine oil. An electric pump before the mechanical pump would probably force more to go in.

Nothing wrong with that idea if the mechanical pump is in good order but then the need doesn't arise.

Exactly, if I do fit an electric pump, I would remove the mechanical one all together.

[Wotname]

Originally Posted by 01kiwijohn

Try a local John Deere Dealer, JD uses a lot of small Yanmars in their commercial mowing and compact utility tractors.
If you decide to go electric, you could hook that into the tank supply line and just pump it through the Yanmar priming pump; that way, no need to change a lot of special, steel, fuel lines.
If you do rebuild that pump, remember to loosely assemble it, then hold the lever at it's maximum stroke position before tightening the screws that hold it together. That way, the diaphragm will not be under stress and will last much longer.

Realized today that we have some JD compact tractors at work so had a look and they had a compact electric pump ( on a 3 cylinder Yanmar engine). Looked like a reasonable alternative!

[GrahamHO]

Originally Posted by Wotname

Realized today that we have some JD compact tractors at work so had a look and they had a compact electric pump ( on a 3 cylinder Yanmar engine). Looked like a reasonable alternative!

Sounds good. I guess that Yanmar are making their marine engines as complete working units that can be dropped into any vessel and work straight off. So they have the mechanical pump as it might not be a good idea to engine mount an electric pump.
On the other hand JD are making complete tractors so an electric pump can be incorporated in the design.