Yanmar 2GM lift pump failing

[lonesoldier0408]

Originally Posted by Wotname

Now there is a rational explanation of how the puncture might cause a runaway!
While unlikely, this explanation is rational and therefore possible unlike the idea of the oil system being involved.

As for the cause of the puncture, here is another wild A'd guess.

You mentioned there were two part numbers; a superseded one and its replacement. Maybe the old one was prone to bending (and occasionally breaking) the retaining plate and the new one was improved. Now I realise you understand your second failure was on the later part number pump but it wouldn't be the first time a box contained the "wrong" item, even if sealed from the factory - especially when they look alike. Were the two pumps marked in any way except for the packaging?

By the way Steve, welcome aboard CF; nice first post and thread. You got us all thinking with this one and that is always a good thing

[emoji106]

[Steveschr]

Thanks guys.

Honestly I don't recall the part numbers and couldn't tell the difference between the pumps.

Out of curiosity, does anyone know if most of the motors have a solid or braided line between the lift pump and the Yanmar filter?

Steve

[boatbod]

Originally Posted by Steveschr

Thanks guys.

Honestly I don't recall the part numbers and couldn't tell the difference between the pumps.

Out of curiosity, does anyone know if most of the motors have a solid or braided line between the lift pump and the Yanmar filter?

Steve

Mostly the GM series had a braided fuel line from the lift pump to the fuel filter and solid lines from filter to the inj. pump.

[four winds]

My 3gm30f has a braided line. But my old service manual shows a solid line.

Many parts are common between 2gm and 3gm.

Someone mentioned the braided line is a new part change for the old solid line. That could be so, I think.

I have a newer pdf manual, so I'll look to see what it shows.

[four winds]

No, not the same as my 3gm as I thought.

The 2gm20 parts manual shows a common rubber hose with clamps and banjo fittings. The part number has been superseded but I can't find a picture. Only eight bucks, probably not braided.

[Steveschr]

Do the braided lines have give to them? I mean would they absorb a pulse of pressure like a rubber hose or would they stay rigid as to the volume?

I had read the braided line superseded the solid line due to the fittings loosening up from vibration but that didn't make a lot of sense.

Steve

[Steveschr]

Oh wait... Four Winds - Just to verify - your manual shows the line between the lift pump and the filter housing as a plain fuel line with clamps?

[boatbod]

One problem I encountered with the braided line is difficulty detecting small leaks. Had one once that leaked so slowly the engine would run normally but not start the next morning without bleeding. It took hours to track down the underlying cause, only given away by a very slight wetness on the braid.

[Compass790]

I should have said the braided line I use has an internal braid( Like std fuel hose) not the external s.s. braid & it works fine. It is used both between the lift pump & fuel filter & between the lift pump & injection pump. I have double hose clamps on the banjo bolts. Vibration on the YSM8 single is severe

[Wotname]

Originally Posted by four winds

No, not the same as my 3gm as I thought.

The 2gm20 parts manual shows a common rubber hose with clamps and banjo fittings. The part number has been superseded but I can't find a picture. Only eight bucks, probably not braided.

FWIW, my 2GM20 has common rubber fuel hoses everywhere from the input to the fuel pump and onwards to the engine mounted filter and then into the injector pump.

Steve, while not exactly an answer to your questions, the following thread may be of some interest to you.

http://www.cruisersforum.com/forums/...lp-155178.html

[four winds]

Originally Posted by Steveschr

Oh wait... Four Winds - Just to verify - your manual shows the line between the lift pump and the filter housing as a plain fuel line with clamps?

Late response, sorry, got power issues on my boat right now.

Yes the parts manual shows rubber fuel hose with clamps and banjo fittings. Google "2gm20 yanmar parts manual " (and service manual) to find a pdf version to download.

That line is not under high pressure so it's good that way.

About the braided line. Mine is mounted in the shape of the letter "U", so I do think it would work well to absorb the vibrations.

[four winds]

So many common parts between the 2gm20f and 3gm30f was wondering why this fuel line is not common between them.

Well, my filter is mounted on the side of the block near the lift pump. But the 2gm20f is a shorter block so no space there for the filter. It's mounted up high over the high pressure injector pump.

Note the solid line on the 2gm20f pic attached. Just looking at the configuration I can see why vibration could loosen the fittings. I think switching to a standard fuel hose was a purposeful, appropiate response by Yanmar.

I wouldn't worry about finding a braided steel line. The banjo fittings are available from Yanmar and probably other sources. The hose and clamps from any good parts store.

Happy to look up the part numbers for the banjos if you wish and you can verify with Yanmar.

[Steveschr]

Four Winds,
I'd appreciate the part numbers for those banjos as I've been unable to find them on my own.

Thanks
Steve

[four winds]

In the attached picture.

Numbers 18 and 19.

No. 18 has changed to a new number,- 101304-59020

No. 19 still the same number.

The sealing washers are 24 and 25, two each of course.

Use these numbers only to help expedite the lookup by the Yanmar dealer. And he/she can then verify they are correct.

[Steveschr]

Awesome. Thank you very much!