LP pump on Yanmar 2GM20F

Oct 29, 2005
2,355
Hunter Marine 326 303 Singapore
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
 
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
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:

Pump.JPG


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

1586883570426.jpeg


Please let us know how it goes.
 
  • Helpful
Likes: ggrizzard
Nov 21, 2012
587
Yamaha 33 Port Ludlow, WA
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.

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
 
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Likes: RoyS
Oct 29, 2005
2,355
Hunter Marine 326 303 Singapore
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.
mermike, that's a good idea replacing bolts with studs. I can also do it for the exhaust elbow 'cos it's always challenging to fit the bolts with one hand and another holding the heavy exhaust assembly AND try to prevent gasket from dropping and in confined space!
No need to wait, I'll Thank you now.

THANK YOU :) :D

Ken Y
 
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Likes: mermike

DJAY

.
Apr 16, 2018
38
Hunter 31 Saylorville Lake
Oh yes. Mermike, thank you so much for the terrific insight! I’d guess that principle will generalize across many applications!
 
Oct 29, 2005
2,355
Hunter Marine 326 303 Singapore
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:

View attachment 177554

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

View attachment 177555

Please let us know how it goes.
Ralph, yes I gonna do it. have to as i ran out of idea as to what is starving my engine. its seems taking out is 10 times easier than putting back...that's what i gathers and mermike's idea of replacing the bolts with studs....I'm that bring the challenge down significantly.
Will let know how it goes. Given the Covid-19 "Circuit Breaker" constraint, i won't be able to complete the job in one visit (actually allowed only 1hr at boat....2hrs if guards don't do their rounds). So let's see if I've and results after following weekend.

Ken Y
 
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
actually allowed only 1hr at boat....2hrs if guards don't do their rounds
Wow :yikes: ! 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.

1587008540318.jpeg


One new pump into the scrap heap.

Use extreme caution to ensure you've hit the target. Good luck.
 
Oct 29, 2005
2,355
Hunter Marine 326 303 Singapore
All, any idea how long the stud bolts for the Fuel Lift Pump (LP Pump) should be?
The bolt size is M6x16, from Yanmar Parts List. I don't have the threaded hole depth so not sure how long a stud bolt I should get. Any idea.

Ken Y
 
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
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.
 
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
OUCH :banghead::mad::banghead::mad::banghead::mad: ! ! ! 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 ? ? ? ?
 
Nov 21, 2012
587
Yamaha 33 Port Ludlow, WA
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.
 
Nov 21, 2012
587
Yamaha 33 Port Ludlow, WA
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.
 
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
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 :p
 
Oct 29, 2005
2,355
Hunter Marine 326 303 Singapore
OUCH :banghead::mad::banghead::mad::banghead::mad: ! ! ! 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 ? ? ? ?
Yes did changed in new ones for both filters. When starved, I unscrew the vent for secondary filter and it was empty on both inlet and outlet. So suspect was Fuel Lift Pump or hose between.

Ken Y
 
Oct 29, 2005
2,355
Hunter Marine 326 303 Singapore
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.
Lucky I got hold of several banjo screws and copper washers before Circuit Breaker kicks in else I'll be kicking myself!

Ken Y
 
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
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 :snooze: !

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:puke:

100_8020.jpg


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.