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Yanmar 100HP Fuel Pump maintenance-free?


svperegrinus@yahoo.com
 

Hello,


Looking at the Yanmar "Operation Manual", there is no mention of maintenance of the fuel pump, nor of any maintenance adjustment.


In the "Periodic Checking List" page of the Yanmar "Service Manual", there is no mention of maintenance of the fuel pump, nor of any maintenance adjustment.


However, in the Yanmar "Service Manual", there is a section called "Overhaul", and it says the fuel pump should be sent to a ZEXEL (the manufacturer of the pump) service center, and there are several pages of parameters and maintenance items for the fuel pump.


So, it seems the fuel pump is a maintenance-free item, except when you overhaul the engine.  Is this correct?  Is there any preventive maintenance for it, or is this a sort of a live and let die kind of component?


Thanks in advance,


Peregrinus

3,400 hours on 4JH3-HTE engine

Fethiye, ancient Telmessos, Asia Minor


greatketch@...
 

We you say "fuel pump" are you referring to the lift pump or the injection pump?


Craig Briggs
 

Hi Francesco,

I think you may be asking more of a philosophy question than an engine maintenance one :-)  

Then again, nothing is maintenance-free forever. There are some signs of overhaul being needed, though. My Perkins developed an unstable rpm at about 4000 hours and I had the pump rebuilt, since I was rebuilding the rest of the engine myself anyway. (The injection pump is not a DIY job.) The shop reported that there was a good deal of internal corrosion from water having entered the system (a prior owner, I sure) and it would likely soon have resulted in a run-away situation with a failed governor. 

I'm now up to 7500 hours and it seems fine. With the pristine way you keep Peregrinus I would assert you're nowhere near a (costly) overhaul of the pump,

Cheers,  Craig SN#68


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

Hello,


Looking at the Yanmar "Operation Manual", there is no mention of maintenance of the fuel pump, nor of any maintenance adjustment.


In the "Periodic Checking List" page of the Yanmar "Service Manual", there is no mention of maintenance of the fuel pump, nor of any maintenance adjustment.


However, in the Yanmar "Service Manual", there is a section called "Overhaul", and it says the fuel pump should be sent to a ZEXEL (the manufacturer of the pump) service center, and there are several pages of parameters and maintenance items for the fuel pump.


So, it seems the fuel pump is a maintenance-free item, except when you overhaul the engine.  Is this correct?  Is there any preventive maintenance for it, or is this a sort of a live and let die kind of component?


Thanks in advance,


Peregrinus

3,400 hours on 4JH3-HTE engine

Fethiye, ancient Telmessos, Asia Minor


svperegrinus@yahoo.com
 

Hello Bill and Craig,

Yes, the question is about the fuel injection pump.  On the Yanmar, it is a ZEXEL NP - VE - 4 / 12 F 1900 R NP1995.

Craig, interesting that you had the pump rebuilt at 4,000 hrs... we are not there yet, and at our current average, will reach 4,000 hrs in about 2 years.  Just like you had the pump rebuilt at engine overhaul time, the Yanmar manual seems to implicate that the pump is to be overhauled at the same time as the engine itself...

... so along these lines... is 4,000 hrs perhaps the horizon for an engine overhaul on an Amel... ???

Yeah, kind of a philosophical question!

Best,

Peregrinus
SM2K N. 350 (2002)


Craig Briggs
 

Hi Francisco,

I definitely did not mean to imply that 4000 hrs is a good time for an overhaul. I think that if your engine is running well that is way too early - like by a factor of 2 or 3.  In my case it was only needed because water had gotten into the fuel and corroded internal parts of the pump. Actually I was rebuilding the engine because a lifting rod had bent and I figured I'd have the injection pump overhauled since I had everything apart anyway and was suspicious about the rpm surge - good thing I did.

So I'd strongly disagree that 4000 is any kind of an engine overhaul horizon. It really depends on how well you "hug" your engine along the way to maintain it and if some random early failure occurs. I see no reason not to expect 10,000 +++ hours. Greyhound buses go a few million miles on their diesels, with periodic rebuilds.

That being said, another criterion may be the years on your engine. My engine has averaged 300 hours a year and I've reached 7500 in 25 years (1992 boat). I wouldn't argue with someone who felt, say, 15 to 20 years is a good time to have a shop overhaul the injection pump (and injectors), even if they had done far fewer hours. There's always a little moisture in the fuel and the inside of the pump and gaskets are subject to corrosion and aging.

So keep hugging your engine and 'don worry, mon!

Cheers, Craig

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

Hello Bill and Craig,

Yes, the question is about the fuel injection pump.  On the Yanmar, it is a ZEXEL NP - VE - 4 / 12 F 1900 R NP1995.

Craig, interesting that you had the pump rebuilt at 4,000 hrs... we are not there yet, and at our current average, will reach 4,000 hrs in about 2 years.  Just like you had the pump rebuilt at engine overhaul time, the Yanmar manual seems to implicate that the pump is to be overhauled at the same time as the engine itself...

... so along these lines... is 4,000 hrs perhaps the horizon for an engine overhaul on an Amel... ???

Yeah, kind of a philosophical question!

Best,

Peregrinus
SM2K N. 350 (2002)


greatketch@...
 

The number that several experienced mechanics have given me is that a well cared for (key words, there) marine diesel will get to the point it needs an over haul between 6 and 12 thousand hours.  That's a HUGE range, and that is not too surprising since it is a very "fuzzy", yes even philosophical, kind of answer.  An overhaul really is a performance based criteria, not something that has an expiration date.

Our 21 year old Volvo has 7,500 hours on it, and runs like a top.  Putting out power at the same rate as it always has based on boat speed and rpm at full throttle.  Based on the criteria above, it might run without a full overhaul for another 15 years...  or it might need one in 5...

An injection pump is a VERY fussy piece of equipment.  There is a reason that they have "tamper-proof" seals on so many of the adjustments.  Overhauling one is a job for true specialists, not the average diesel mechanical shop.  Clearances and settings are extremely small, and the test equipment needed to be sure it is running well is very expensive.  On the positive side, they can run a very, very long time without a problem, and they are very rarely the cause of problems.

In general, if the engine is coming apart anyway, you can send the injection pump (and injectors) out for testing.  If they test well, an overhaul is not needed.


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

Hello Bill and Craig,

Yes, the question is about the fuel injection pump.  On the Yanmar, it is a ZEXEL NP - VE - 4 / 12 F 1900 R NP1995.

Craig, interesting that you had the pump rebuilt at 4,000 hrs... we are not there yet, and at our current average, will reach 4,000 hrs in about 2 years.  Just like you had the pump rebuilt at engine overhaul time, the Yanmar manual seems to implicate that the pump is to be overhauled at the same time as the engine itself...

... so along these lines... is 4,000 hrs perhaps the horizon for an engine overhaul on an Amel... ???

Yeah, kind of a philosophical question!

Best,

Peregrinus
SM2K N. 350 (2002)