"Freshening Up" Yanmar at 2000 hours

[Dockhead]

I am in general very happy with my Yanmar 4JH3HTE (that's the 100hp, turbocharged, intercooled version of the venerable 4JH3 engine). When I bought that boat, it had 830 hours on it. Now, five years later, it is pushing 2000.

In these years I've only had three problems with it:

1. It smokes like a chimney when it's cold, and has done since the day I bough it.
2. I had a very tiny air leak in the fuel system -- apparently through a defective fuel filter -- which caused the engine to cut out at higher revs. A maddening problem which neither I nor a number of crack diesel mechanics could diagnose. This lead to all kinds of unnecessary work -- turbo washed and checked, injection pump taken off and sent for full testing, replaced all of the injectors, etc., etc., etc.
3. I had a small problem with the starter solenoid.

Other than those things, it runs like a top, smooth and powerful, and starts if you even look sideways at the start button. I mean, this engine doesn't even get through one whole revolution with the starter motor before it roars to life, even in below freezing temperatures. I have never used the air preheat and don't even know if it works. Never needed.

It doesn't use any oil, and doesn't leak any. I added half a liter once when I went 200 hours between changes, but otherwise never.

So in general, I'm very pleased. I have learned to live with the smoke, which mostly goes away after the engine is warmed up well. My surveyor told me it's nothing to worry about.

But 2000 hours is 2000 hours, and this winter I'm planning to do some preventative maintenance.

My draft program is as follows:

1. Adjust valves (never done it before; the Yanmar dealer who serviced the engine when I bought the boat said no need to bother, but now I'm wondering whether I should have taken that advice).
2. Repair or replace exhaust elbow. The massive stainless steel unit now has a pinhole leak.
3. Replace all engine hoses (I already did this once; when I bought the boat).
4. Replace all belts (ditto).
5. Remove the heat exchanger, clean out thoroughly, inspect. The engine runs rock steady at the thermostat opening temp (80C) no matter what the load, but after 2000 hours I figure it's time for this. Do I need to carry a spare?
6. Ditto the engine oil cooler, transmission oil cooler, intercooler.
7. Check injection timing.
8. Wash turbo with the special, expensive Yanmar snake juice.
9. Drain coolant, flush out with distilled water, replace with new coolant.
10. Replace motor mounts as necessary to eliminate knocking at idle.
11. Clean out vents from antisiphon loops.
12. Replace start batt. Which is 13 years old!!! Has lasted this long because its work is trivial, and it's not used for anything else (start system is completely separate from house batts, and I have two separate alternators). But I don't want to push my luck!


What do you diesel gurus think -- does that sound about right? I'm not including the usual annual jobs like oil & filter changes, impeller, etc.


What about the fresh water pump? Should I just leave it and carry a spare, or do they typically go bad about this time? And the salt water pump? Do I need to carry a whole spare, or do they tend to last?

Anything else? I am presuming I don't need to worry about the waterlift muffler or exhaust hose if it's still working with no leaks.

One other potential item from the propulsion system: I have a PSS shaft seal which has worked flawlessly over the years, but surely at 2000 hours it's nearing it's sell-by date, no? Should I replace it preemptively, and keep the old one as a spare? This is one of those things which, for obvious reasons, you don't want to have to wait for it fail. Or do they last 10,000 hours?

I have a 110 amp (x 24v) Leece-Neville school bus alternator which does hard duty. I run all kinds of loads -- even run my washer/dryer (I confess) off the inverter when the engine is running, so I guess you can say that I treat the alternator in a semi-abusive way. So far it just keeps on ticking, but is it time to have it taken apart and inspected, new brushes, etc.? Or is it too soon for that?

Last question: I don't much like the fact that the Yanmar silver-blue-gray paint is failing in places and going over to rust. Is this external rust any concern? Some rigid steel pipes are rusting which makes me nervous. Should I do something with this, or don't worry about it?


As always, I will be grateful for any advice!

[sailorchic34]

I would just rebuild the existing water pump and raw water pumps, New bearings and seals, as they should be getting ready to drip sooner then later. Or carry spares of both.

With the engine starting that easy,I would not worry about the injection timing, It's obviously spot on. Can't hurt to check the valve clearance.

On the intermittent air leak at high RPM's, have you changed the lift pump, or install a side arm electric pump.

On rusty bits, passivate with phosphoric acid and repaint. Just brush on the phosphoric acid, no need to rinse.

[Hudson Force]

I have 6,562 hours on my 4JH3E naturally aspirated Yanmar. I do, of course, keep to a rigorous maintenance schedule and I've been checking my valve clearances every 500 hrs; however, I rarely find any need to make an adjustment. I have been frustrated by the need to replace my oil pressure sensor three times, but my biggest failure to date has been the failure of a metal flange on the oil cooler.



Fortunately it was on the water side and not the oil side!




My engine's paint is pretty good, but I am seeing a few small spots that need attention. I've done nothing with my mixing elbow or fresh water pump over these hours. I know, yes I do know, that I should have changed the hoses and belts over these 6,500+ hours, but I have inspected them, but I've done nothing except to change a couple of water hoses that were showing some wear.

[Dockhead]

Originally Posted by Hudson Force

I have 6,562 hours on my 4JH3E naturally aspirated Yanmar. I do, of course, keep to a rigorous maintenance schedule and I've been checking my valve clearances every 500 hrs; however, I rarely find any need to make an adjustment. I have been frustrated by the need to replace my oil pressure sensor three times, but my biggest failure to date has been the failure of a metal flange on the oil cooler.



Fortunately it was on the water side and not the oil side!




My engine's paint is pretty good, but I am seeing a few small spots that need attention. I've done nothing with my mixing elbow or fresh water pump over these hours. I know, yes I do know, that I should have changed the hoses and belts over these 6,500+ hours, but I have inspected them, but I've done nothing except to change a couple of water hoses that were showing some wear.

IIRC, your engine is less than 10 years old, right? Keep in mind that some things are more time-limited than hours-limited, and sometimes I think that time is nearly all that matters, considering how badly engines which are seldom run hold up. I guess to be accurate, probably engines run less than 200 or 300 hours a year are not deteriorating less than engines which are run more, and engines which are run less than 100 hours a year are probably deteriorating more. Especially if maintenance is laxer (neglecting the time-defined maintenance intervals, as is usual) with the less run engines.

My engine was run 830 hours in the eight years of her life before I bought her, which is probably on the edge of dangerously little. I have run it more than 1100 in five years, which is a bit better, and other than not adjusting the valves, I've been pretty energetic with maintenance.

What do you do, by the way, with impellers? I've only replaced mine I think twice in 1100 hours. I pulled the first one out after 300 or 400 hours and it was just like new, without the slightest sign of wear or any cracking, so I just put it back in. Then after another 200 or 300 hours I replaced it on principle. Another time I ran the engine for a few minutes with the sea cock off -- idiot I was. The impeller looked fine after that (my genset impeller, by contrast, literally explodes if I run it for even a few seconds with the sea cock turned off -- I wonder why the big difference?). I ran it a whole summer but then replaced it just out of principle, although it looked fine. So I have come to the conclusion that there is no need to change the impellers in this engine annually. I think two or three years is fine -- what do you think?

[Hudson Force]

Originally Posted by Dockhead

.... your engine is less than 10 years old, right? ............ ......... what do you do, by the way, with impellers? ..........

My engine is 14 years old and I do agree that there is an important factor with use as well as age. I don't know the answer to the use and age ratio, but I would agree that more engines suffer from too little use than too much age. I have also found that quality impellers seem to last well beyond the one year replacement schedule. I've been pleased wih the Johnson impellers, but I did have a couple of Globe impellers that failed prematurely, .....



...as shown in this photo where the inner core has broken down. Quality seems to vary.

[Dhillen]

Originally Posted by Dockhead

IIRC, your engine is less than 10 years old, right? Keep in mind that some things are more time-limited than hours-limited, and sometimes I think that time is nearly all that matters, considering how badly engines which are seldom run hold up. I guess to be accurate, probably engines run less than 200 or 300 hours a year are not deteriorating less than engines which are run more, and engines which are run less than 100 hours a year are probably deteriorating more. Especially if maintenance is laxer (neglecting the time-defined maintenance intervals, as is usual) with the less run engines.

My engine was run 830 hours in the eight years of her life before I bought her, which is probably on the edge of dangerously little. I have run it more than 1100 in five years, which is a bit better, and other than not adjusting the valves, I've been pretty energetic with maintenance.

What do you do, by the way, with impellers? I've only replaced mine I think twice in 1100 hours. I pulled the first one out after 300 or 400 hours and it was just like new, without the slightest sign of wear or any cracking, so I just put it back in. Then after another 200 or 300 hours I replaced it on principle. Another time I ran the engine for a few minutes with the sea cock off -- idiot I was. The impeller looked fine after that (my genset impeller, by contrast, literally explodes if I run it for even a few seconds with the sea cock turned off -- I wonder why the big difference?). I ran it a whole summer but then replaced it just out of principle, although it looked fine. So I have come to the conclusion that there is no need to change the impellers in this engine annually. I think two or three years is fine -- what do you think?

Dockhead,

My experience with impellers has been exactly the same as yours. I change them every 500 hours, just because. Never have I seen any issues with the impellers - they come out looking new.

As far as replacing/rebuilding the raw water pump. Uh, no. If your engine is the same as mine (I have the 4JH3-HTE) you actually need to remove the engine mounts, disconnect the prop shaft and then LIFT the bloody engine to remove that water pump to work on it. Who in their right mind would design something so asinine when the rest of the engine is as close to flawless as you would want?

I would devote time and energy toward something more profitable.

Cheers.

Dhillen

[sailcrazy]

Speaking of "freshing" up your engine....although we had never done it, a mechanic we employed after having some issues while cruising in Turkey "strongly" recommended we should run our engine up to max/near max RPM for 15-20 minutes after every 4-5 hours of motor-sailing. We typically run our 4JH-TE (55hp, turbocharged) at 2000-2300 RPMs while under way, and the max RPM is 3600. We had never heard that advice before, and have had some mechanics say..."absolutely, you need to do that", while others have said absolutely NOT...Would you take your car and run it at full throttle every 5-6 hours of driving?.. I've asked every mechanic we've come across just to get their opinion We have been doing it, and based on the carbon particles on the swimm platform and the smoke that comes out of the exhaust...maybe it's not a bad idea? But I've never heard of another cruising boat do it. Any thoughts?

[weavis]

Aww Dockie.

Give up and just go buy the Gunboat.

Ill crew for you.

[svfraidknot]

i have 2 yanmar 4jh2e on my boat still going great i have a brand new PSS shaft seal for a one inch shaft i cannot use ,, i have 300 invested in it here in panama ,, my v drive clearance on my cat gives only 4 inches to work with a pain even to change a packing gland ,, if you change yours and it is one inch shaft perhaps we could work a trade ???

[Hudson Force]

Originally Posted by Dhillen

Dockhead,

My experience with impellers has been exactly the same as yours. I change them every 500 hours, just because. Never have I seen any issues with the impellers - they come out looking new.

.................................................. ..........
Cheers.

Dhillen

Just one more observation about impellers. I agree with rarely finding problems with quality made impellers, but I did discover long ago a behavior that can chew one up very fast.

If your anchoring in fairly shallow water on coral marl or any substrate with light sand or spicules that may remain suspended in the water do not motor forward over the cloud of suspended grit brought up by your anchor. Some of these particles that are common in the Florida Keys and Bahamas will make quick work of your impeller! The same risk can occur if you're rinsing this type of material off your ground tackle while motoring forward.

[Vasco]

I have a 10 year old 4JH3E with over 2000 hours on it. Last season I replaced the water pump (leaking slightly) and the oil cooler. Took the oil cooler off to check it and when cleaning it, went right through the brass or whatever it is. It was paper thin. There is no anode in the oil cooler and it gets thinner every year. Replaced the slave solenoid quite a few years ago. Oh, when I replaced the water pump it came with a new impeller. The old one was the original! Never did change it before getting the new pump as it's a bitch to get at. Lasted over 2000 hours. Right after I bought my boat Yanmar came out with the 4JH4E where the impeller is a snap to replace. In the 3E it's easier to remove the whole pump to change the impeller than to try just replacing the impeller.

[Terra Nova]

A couple I know were preparing their yacht for their world cruise. Their perfectly fine diesel had ~2500 hours, IIRC. And they somehow allowed themselves to become convinced that a rebuilt exchange should be done, to preempt problems in the field. The engine was replaced.

As their departure window approached, they now had an engine which produced less power, had less oil pressure, and ran so roughly, that they were beside themselves. I didn't follow the ensuing scramble to make the repairs before they ran out of time. But I suggest you heed "If it ain't broke, don't fix it". A couple thousand hours is nothing for these engines, if maintained as well as you describe.

HF--good post.

[rognvald]

Dockhead,
Based upon your list I would:
1. check valve tolerances with a feeler gauge. If they are fine, your done.
2. pull mixing elbow to be certain it is not carbonized or that the
wall is eroded between exhaust gas/water. Replace gasket.
3. replace hoses as needed not because you want to change them.
Check for cracks and undue softness.
4. ditto for belts (check for cracking)
5. remove heat exchanger. Boil if needed and replace "O" rings.
6. Don't have coolers on mine. Cannot advise.
7. If it runs fine, why check the injection timing?
8. Turbo--can't advise but on automobiles, turbos are serviced when
they leak and malfunction.
9. Drain coolant. Add cleaner. Remove cleaner after 5 hours run time.
Replace with pre-mixed coolant.
10. Are the motor mounts bad or do they need to be adjusted? Replace
if bad. Adjust if needed.
11. Check battery for voltage. If marginal replace.
12. Carry an extra water pump. When it fails, replace and rebuild old
pump.
13. Paint engine as Sailor Chic advised.

Your concerns are good and show that you are a conscientious person which will pay great dividends in your future cruising adventures. I hope this is helpful. Good luck and good sailing.

[Kenomac]

Before you take this too far, remember, "if it isn't broken... don't fix it."

[atoll]

might want to get the injector nozzels serviced,although they may run fine,2000 hours is about the service interval for many types of injectors,they do get worn over time.