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Yanmar Diesel Lift Pump


Duane Siegfri
 

I was going over the notes I made from a seminar the Mac Boring did for the care of Diesel engines.  They recommended you change the low pressure lift pump on Yanmars after 8 years whether there were problems or not.


Any diesel guru's out there have an opinion on this issue?


Duane

Wanderer, SM#477


svperegrinus@yahoo.com
 

Duane,

What is the reason for the recommendation?  What problems are likely to arise from not replacing this pump?

Thanks in advance,


Peregrinus
SM2K N. 350 (2002)


Duane Siegfri
 

Theie point was, they are prone to fail after that period to such a degree it's better to just replace.


Duane Siegfri
 

Ok, this might seem a bit wierd, but after posting the original note in June, my Yanmar 4JH3-HTE low pressure lift/priming pump started to leak fuel (it was visible on top of the fuel filter) just recently.  It has 2,980 hours and in the Mac Boring Diesel Engine Class I took they recommended you change it at 2,500 hours.

It was a simple swap for a new part that cost about $60.  I didn't know Yanmar made any parts for less than a couple hundred!

Duane
Wanderer


greatketch@...
 

Duane,

You think Yanmar parts are expensive....  take a look at the Volvo price list and feel blessed!

Bill Kinney
Harmonie



---In amelyachtowners@..., <sailor63109@...> wrote :

Ok, this might seem a bit wierd, but after posting the original note in June, my Yanmar 4JH3-HTE low pressure lift/priming pump started to leak fuel (it was visible on top of the fuel filter) just recently.  It has 2,980 hours and in the Mac Boring Diesel Engine Class I took they recommended you change it at 2,500 hours.

It was a simple swap for a new part that cost about $60.  I didn't know Yanmar made any parts for less than a couple hundred!

Duane
Wanderer


rossirossix4
 

My understanding is that the lift/low pressure pump on the Yanmar is integrated into the injector pump and that the priming pump (I carry an extra) is separate.  I am basing this on the Yanmar 4JH3 HTE Service Manual and the Parts List.  The shop manual shows the "feed pump" as integrated and the parts manual doesn't show a separate part, only a priming pump.

There was an earlier post about the need to replace the low pressure pump on a scheduled basis (that it would not supply fuel at an acceptable rate) but it seems that would entail replacing the injector pump or a component of the injector pump.  Does anyone have a clarification on this?

Bob, KAIMI SM429
Currently in Saint-Tropez


rossirossix4
 

Hi Duane (and Bill),

Yes, I am thinking it is the manual priming pump and not really the low pressure pump.  When I saw the comment about Mac Boring recommending changing the low pressure on the Yanmar it caught my attention--thinking that it would cause fuel starvation or problems with the HP pump or leaking.  

I had a low pressure pump failure (it is separate) on my Santorin's Perkins M50 and leaked through a weep hole designed to ensure that diesel fuel did not enter the engine's crank case.

Don't know if the integrated Yanmar low pressure ever fails but back in the day my Mercedes 220 D had a manual priming pump.  One time the low pressure/feed pump failed but you could run the engine even at high rpm by hand pumping the priming pump.  No way to test this but manning the priming pump might get you into port!

Shout out---Duane, Pat, and Bill K, et al--I've had really good luck with Yanmar and Onan parts up at Bay Shore Marine at Bert Jabins Yacht Yard.  They are also good about shipping parts.  They market a really nice impeller puller pliars that has worked very well on the Yanmar and Onan.
Bob
KAIMI