Yanmar HP fuel pump question

[Captain Bill]

I recently had my injectors rebuilt on my 3jh3e(epa) engines. During the reassembly a piece of paint flaked off of a fuel tube fitting on the fuel pump end and was caught between the tube and the delivery valve guard on the pump when I tightened it. This has apparently damaged the metal to metal seal between the two parts slightly as they now will not seal. They only seep and not spray large amounts of diesel and under a microscope I cannot see any obvious damage to the tube end and at this point have not removed the "guard", but since it won't seal I assume there is damage and have ordered a new tube and delivery valve guard on the pump and a new o-ring that seals the guard to the lower parts of the delivery valve assembly. It appears from the exploded view that I can simply remove the guard from the pump, replace the o-ring, and install the new guard. The service manual does not address this but only gives instructions for disassembly and reassembly of the whole pump mechanism. Can anyone who knows these pumps in detail tell me if this is as simple as it looks on the surface or is the whole thing going to turn into a disaster when I remove the old guard?

[skipperpete]

Hi Captain Bill, did you change the delivery valve holder (guard) yet? It’s not difficult but it’s one of those places where you should use a torque wrench , and as you already know, cleanliness is extremely important. It can be tricky getting the spring to sit properly on the delivery valve, yanmar suggests using a length of wire down the hole in the holder to help with this. I’m guessing you already got this done, hopefully with success.

[Captain Bill]

I have and it was totally successful with one caveat. I got the old one exchanged then the one next to it started leaking around the o-ring. Since the first one was hard and flat I tried to get another one but it was not available quickly but my local hardware store had the proper size in stock for 1/6 the price so I changed all three. I did use a torque wrench since the manual did spec a torque. I am now in the Bahamas and about 40 engine hours post repair and it has not leaked a drop. I know I'm a sailboat but the crossing window was limited so I motored most of the way because as usual the wind is always coming from where I'm going.