LP pump on Yanmar 2GM20F

Ralph Johnstone · Apr 14, 2020

Hi Ken,

1. The oil level is well below the arm for the LP pump.

2. If you're OCD like myself, put a couple of pieces of masking tape over the opening to avoid dust getting into the hole. If you're like normal folk, leave it open as it's unlikely anything is floating around in the air.

Are you really going to try to get that pump back in there:

You'll be trying to get the arm to land on the appropriate cam and it's none too friendly.

Please let us know how it goes.

mermike · Apr 14, 2020

I strongly encourage you to install a pair of studs (I think they're M6) with matching nuts and lock washers, and save the bolts for something more appropriate. You can thank me later.

Ken13559 said:
1. Do I suppose I don't need to lower my crankcase oil when I remove the LP fuel lift pump?
2. I probably wouldn't be able to put back the pump same day, given the limited time I have on board (due to Covid-19 restrictions/Circuit Breaker). I should put something to block the hole when the LP pump is out. Right?

Ken Y

DJAY · Apr 15, 2020

Wish I had thought of that....

mermike · Apr 15, 2020

Me too. Now I know. Never again.

DJAY said:
Wish I had thought of that....

DJAY · Apr 15, 2020

Oh yes. Mermike, thank you so much for the terrific insight! I’d guess that principle will generalize across many applications!

Ralph Johnstone · Apr 15, 2020

Ken13559 said:
actually allowed only 1hr at boat....2hrs if guards don't do their rounds

Wow

! You people are really taking this seriously and I certainly applaud you for it. I know we could be doing better.

As far as replacing the bolts with studs in the block, in theory a good idea but still difficult to do if you're working blind.

Your target is to get the arm of the lift pump dead centre ON the "Fuel feed pump cam" as shown below. I thought I had it but it slipped off to one side and when the bolts were snugged , the arm of the pump was bent.

One new pump into the scrap heap.

Use extreme caution to ensure you've hit the target. Good luck.

Ralph Johnstone · Apr 16, 2020

Ken13559 said:
how long a stud bolt I should get

Studs are cheap. I'd arm myself with pairs of approx. 20 and 24 mm. studs before getting to the boat. If you want a guarantee that you do it in one trip, maybe a couple of 30 mm. and cut down to the desired length.

Ralph Johnstone · Apr 18, 2020

OUCH

! ! ! What an absolute #$^%&^* PITA.

You're not going to find anything too exciting in the secondary filter unless it's never been changed. You DID check both filters before getting into this, didn't you ? ? ? ?

mermike · Apr 18, 2020

Check all the banjo bolts for tightness and especially for cracks. If you've reused the copper washers replace them. If your bleed screws (one on the secondary filter and one at the HP pump) are looking well used, replace them too.

mermike · Apr 18, 2020

Back to the studs for a moment. After having carnal relations with the motor I finally got the bolts threaded and the pump installed. I fired it up and it was leaking oil. After pulling it off again, I found the gasket had slipped off. Wrestled with it one more time, this time successfully. Studs, next time. No question.

Ralph Johnstone · Apr 18, 2020

mermike said:
After having carnal relations with the motor I finally got the bolts threaded

That's one thing I never tried when I damaged the lever arm of my pump.

- do you think it helped in any way
- did your wife approve
- what about the children
- neighbours
- did you light up afterwards with all of the combustibles around
- would you do it again

mermike · Apr 18, 2020

@Ralph Johnstone :
No.
No.
They've seen worse
Weren't around
Good thing it's diesel
NOOOOOOO!

Ralph Johnstone · Apr 20, 2020

Ken13559 said:
When starved, I unscrew the vent for secondary filter and it was empty on both inlet and outlet.

I can't get any sleep until you solve this thing

!

With the secondary filter (SF) being empty, sounds like the lift pump is doing a fine job of getting all the fuel it can before it starts sucking air out of the SF.

If you're really serious about solving this then close the fuel supply valve on the top of your fuel tank and then remove the inlet hose to the SF. Take the fuel inlet hose in your mouth and suck for all you're worth

If you're not THAT serious about the problem, then put the vinyl hose from your oil vacuum suction pump (Pela type) into the end of the fuel line which you opened up. Wrap the vacuum tube with tape to ensure you've got an airtight seal.

If you can't maintain a vacuum, you've got an air leak in the fuel line, or primary filter, or fittings, or etc, or etc. Take your pick.

Good luck as always.

LP pump on Yanmar 2GM20F

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