Lift pump on my Yanmar 1gm10, is it necessary?

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niallw70

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Hi All, I've had a problem with a leaking lift pump on my 1gm10. On removal I found the female thread on both inlet and outlet side of pump almost completely stripped, indeed the remains of the thread came out with the banjo bolts. I was about to check and find out how much a replacement part would cost, when I had the thought, do I even need one? My fuel tank base is about 8 inches above the level of my primary filter and maybe 10 inch above the secondary (engine mounted) small filter. Surely my fuel can be fed to hp fuel injector pump by gravity alone?
I had some spare hose, so was quickly able to connect up a line from primary to secondary filter, bypassing the lift pump. Bleeding the air out was very quick (before I had to manually operate lift pump lever 20-30 times to remove bubbles). Engine started up first time, infact I'd say it fired almost on the first stroke whereas before it could take several strokes to fire.

I've only just tried an engine test the once with boat on mooring, with the new arrangement. My wife pointed out might this not be a problem if boat is heeled over and my fuel tank level goes below that of the engine. I've dismissed this, if the boat is heeled over that much, she should have the sail power to get out of whatever situation we are in.

Am I missing something? Has anyone else tried this and found a problem with bypassing the lift pump? I'm intending to remove the lift pump altogether and replace with a bit of SS plate that I will cut to size. Btw, if anyone is needing a yanmar lift pump for spares or repair, PM me. Many thanks.
 
Temporary fix. The banjo bolts are opposite each other so use a small G clamp across the pump to squeeze them tight. Make sure that the copper washers are annealed or swap them for dowty washers.
 
2gmf on my generator.
problems with liftpump (leaking air in the circuit forcing the need for daily bleeding....)
bypassed it completely for a season. Main tank is rather high (1m high) high pressure pump sits somewhere in the middle (heightwise)
As long as the tanks were quite full, all fine.
As soon as tanks fell to whereabout the h/p pump level is, starting problems started. Mind, if it eventually started, h/p seemed to be able to suck diesel and work at 3k rpm (constant speed for my generator) without problems.
Ended up buying an electric pulse priming pump (50euro) and fitting a simple blanking plate where the liftpump was.
No problems ever since, but you have to find how to wire it so that pump only works when engine is running.

so you may get away with it.

V.
 
Thanks for the replies. I'm interested in the electric primer pump suggestion. I could easily wire it into my alternator output. But my engine has purely mechanical speed/load fuel governor system. Might a electrically powered pump interfere with my fuel governor system?
 
Nah. Any click-clack pump (thinking Morris Mascot type) will pump until a bit of pressure is achived then stop and wait for pressure to fall,- then start again.

Power feed from start key will do fine.
Plenty of options on the interweb, just need to make sure the flow rate is adequate which realy is easy for an engine burning about a table spoon one liter per hour ;)

s-l1000.jpg
 
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for the record the one I have in my yanmar looks just like the one ChromeDome posted above.
Note, that such pumps will let fuel flow through them when not in operation (in one direction obviously) so wont make your engine stop if for some reason they fail. Makes you feel better I guess...

V
 
vas said:
2gmf on my generator.
problems with liftpump (leaking air in the circuit forcing the need for daily bleeding....)
bypassed it completely for a season. Main tank is rather high (1m high) high pressure pump sits somewhere in the middle (heightwise)
As long as the tanks were quite full, all fine.
As soon as tanks fell to whereabout the h/p pump level is, starting problems started. Mind, if it eventually started, h/p seemed to be able to suck diesel and work at 3k rpm (constant speed for my generator) without problems.
Ended up buying an electric pulse priming pump (50euro) and fitting a simple blanking plate where the liftpump was.
No problems ever since, but you have to find how to wire it so that pump only works when engine is running.

so you may get away with it.

V.
Click to expand...
On my generator I removed the mech fuel pump and replaced with a cheap Facet type Chinese copy electric pump. I have an illuminated switch on the control panel I switch on before starting the engine. The fuel system is now super easy to bleed. I had no end of trouble with mech pumps so won't be going back to those any time soon. I carry a spare lecky pump just in case
 
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geem said:
On my generator I removed the mech fuel pump and replaced with a cheap Facet type Chinese copy electric pump. I have an illuminated switch on the control panel I switch on before starting the engine. The fuel system is now super easy to bleed. I had no end of trouble with mech pumps so won't be going back to those any time soon. I carry a spare lecky pump just in case
Click to expand...
+1 only it took me a starter, a full rebuilt, injector check, a few more bits before getting the El lift pump and sorting all my problems :rolleyes:
And to get insult to injury, now with the lifepo4 I've only used the Genny 2h during the season...
 
vas said:
+1 only it took me a starter, a full rebuilt, injector check, a few more bits before getting the El lift pump and sorting all my problems :rolleyes:
And to get insult to injury, now with the lifepo4 I've only used the Genny 2h during the season...
Click to expand...
We use ours to make water only. 15 to 20 mins per day whilst we liveaboard. It works out nicely at 75-100 hrs per season. One oil change a year. I think it's better run it often. 2 hrs per season might be a tad short?
 
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