2gm20f High Pressure Fuel Pump Re-Assembly

[Capn Mike]

Hello,
I am trying to re-assemble the high pressure fuel pump (pn 728271-51101) on my Yanmar 2GM20f Engine. I removed it because it was froze up and not pumping. Now I've cleaned the parts and it looks good, but I don't know exactly how to get it back together.
There are 2 things I am really having trouble with:
1. I don't know which way to allign the pinion gears (pn 124950-51510).
and
2. I don't know how to get the plunger (pn 128170-51101) inside the spring (pn 124950-51190) and then get them both into the pump.
I fear that putting this together will require some special tools.

I've scowered the internet, and taken it to a diesel mechanic. I have not found any re-build information in the internet, and my mechanic straight up said he did not know how to put it together.

I have a good diagram of how all the parts are supposed to go together, but actually making them go together is not an easy task.

Should I just drop about $950 on a new pump?

Thanks,
Mike

 

[woodster]

look for a repair shop that does injectors and pumps and have them fix it

 

[Benny17441]

Sorry, that is one job I have never tackled. I spoke with the shop manager of one of Yanmar's largest dealership in Florida a while back about rebuilding a high pressure pump and he recommended I get a new one. He mentioned two factors, 1) the parts to rebuild and the labor will come close to what a new one sells for, 2) The tolerances between the plunger and cylinder are real tight and any little left over imperfection may reduce its life. I was working on a frozen pump for a friend and we got lucky as we submerged the pump in a cleaner for a couple of days and then pulled on the plunger and it released. A lot of water had gotten into the fuel tank and apparently cranking the engine had gotten water into the pump and caused it to jam. Your situation is different as you have cleaned the parts and just intend to reassemble it with the same parts. Perhaps it might be worth it to take it to a Yanmar shop and let a tech look at the components and see which are in good enough condition to be reused and also get an estimate for the labor of them putting it together. If it is significantly less than the price of a new one it may be worth the chance. This is a diagram for the 3GM pump which should be similar. Good luck, them things are terribly expensive .

 

[kloudie1]

Mike, here is the official assembly stuff for the injection pump. Scrroll down to 3-18 for your pump. Good Luck