Taking care of a Yanmar 4JH3E, 55hp

[bshillam]

New to the world of cruising diesels I thought I would find out if there was more I should be doing in terms of maintenance for my little Yanmar,
Yearly oil changes 100-150 hours with new filter
Yearly anti-freeze/coolant change
Yearly tranny fluid change
5-6 years pulling the exhaust elbow to inspect/replace
Belts inspected every or every other trip
Every two years changing out the impeller
Thoughts on what I might be missing?

 

[MurrayM]

Sounds like you have it covered, but how about fuel filters (which you probably forgot to list) and regular romps?

Do you have the operation and service manuals? They have the information you're looking for, such as timetables for when different parts need servicing, how to warm up and shut down, and when/how to check the oil level...(for some reason our manual says to check 3 minutes after shutting down - yours will probably be different).

I recently got the parts catalog for our Yanmar and it's a gold mine of information besides parts numbers.

How many hours does it have?

 

[Nomad Willy]

Inspect the exhaust manifold carefully (especially the front) making sure sea water isn't leaking down on critical engine parts below. That was a problem on my 3HM35F Yanmar on my previous boat.

 

[LarryM]

I have the same Yanmar. The only things I might suggest you add to your checklist are:

1. Every couple of years de-scale or flush the raw-water side of your cooling system. I use Rydlyme, but Barnacle Buster, Trident or white vinegar work as well. After flushing, closely examine the exterior and interior of the engine oil cooler mounted across the back of the engine. They have been known to fail if they become corroded. There are no zincs on this engine, but the alloys were designed to work without them. I have read that there was an engineering change in the cooler material. The PO of my boat had a premature failure at 600 hours. The replacement unit still looks pristine 1,000 hours later.

2. Check raw water impeller annually. I installed a Speedseal Life pump cover and it really makes it easier to do.

3. Adjust engine valves every 1,000 hours.

4. Check the torque on the engine-mounted fuel filter mount. They have been known to loosen from vibration.

5. Check the contacts on the engine stop relay for any signs of corrosion. Clean and lubricate with Corrosion-X or similar. Same for the oil pressure sender connection.

6. Check the Yanmar engine mounts. They are very flexible and the factory recommends changing them every few years, but no-one I know does that. If they are compressed or cracked, they can introduce some significant shaft alignment issues. I just replaced mine at about 12 years, and the shaft was definitely out of alignment due to the worn mounts.

7. You might perform oil analysis with your oil changes to keep track of the chemistry as the engine ages.

I am very satisfied with the 4JH3E and can't imagine my boat with anything else. They certainly don't work hard in a W30, and should last a very long time with proper care.

Good luck,

Larry
M/V Boomarang

 

[markpierce]

Sounds like a mechanic's $$ dream.

 

[N4712]

Sounds like a mechanic's $$ dream.

All of that's pretty simple stuff, except for the valve adjustment.



On another note, changing the tranny oil every year? We usually change ours every other year.

 

[LarryM]

All of that's pretty simple stuff, except for the valve adjustment.

Actually, even the valve adjustment on a 4JH3E only takes 20 - 30 minutes.

You will need a 0.2mm (.008") feeler gauge, some basic hand tools and a rag. The valve cover gasket is actually an o-ring and probably won't even need replacement.

Caution, have an assistant press and hold the stop button while you turn the engine, or crack the injector tube nuts. These engines can start very easily!

With the engine stone cold, remove the valve cover and rotate the engine until the #4 (front of engine) Int and Exh valves are at "rocker position" then adjust #1 Int and Exh, #2 Int and #3 Exh.

Rotate 360 degrees and adjust #2 Exh, #3 Int, #4 Int and Exh.

Replace the valve cover, tighten the injector nuts if loosened and your are done. Easy breezy.

Have fun!

Larry
M/V Boomarang

 

[N4712]

Actually, even the valve adjustment on a 4JH3E only takes 20 - 30 minutes.

You will need a 0.2mm (.008") feeler gauge, some basic hand tools and a rag. The valve cover gasket is actually an o-ring and probably won't even need replacement.

Caution, have an assistant press and hold the stop button while you turn the engine, or crack the injector tube nuts. These engines can start very easily!

With the engine stone cold, remove the valve cover and rotate the engine until the #4 (front of engine) Int and Exh valves are at "rocker position" then adjust #1 Int and Exh, #2 Int and #3 Exh.

Rotate 360 degrees and adjust #2 Exh, #3 Int, #4 Int and Exh.

Replace the valve cover, tighten the injector nuts if loosened and your are done. Easy breezy.

Have fun!

Larry
M/V Boomarang

Well then there you have it folks!

 

[markpierce]

I'll continue to leave valve adjustments to my mechanic. And as for sparkplugs, I'll leave those to the sparkplug fairy.

 

[bayview]

changing coolant yearly is a bit much. Does the engine call for an anti cavitation coolant additive, often called SCA?


By all means see what the makers handbook has to say. They are usually very detailed.


Of course you do want to verify rated RPM propping and participate in that discussion.

 

[bshillam]

Every year for coolant sounds excessive, but that is what Yanmar recommends.

 

[bshillam]

It only has 800 hours so no vavle adjustments yet I guess. I don't know if this is "normal" for a cold diesel or Yanmar but when first started the idle isn't steady. I raise the RPMs to about 900-1000 and it stays idling fine. Otherwise the idle will pulse up and down for about three minutes. I read in the owners manual about a high idle pull but mine has none.

 

[LarryM]

changing coolant yearly is a bit much. Does the engine call for an anti cavitation coolant additive, often called SCA?

I researched this subject a couple of years ago. When I contacted Yanmar they referred me to Mac Boring & Parts Co. who provided the following information in their "Published Yanmar Service Bulletins" document.

Regardless of the recommendation of the coolant/antifreeze manufacturers it is YANMAR'S requirement that the solution is changed every 500 hours (On the YANMAR Model 6LP 250 hours) or once a year whichever comes first.

We do not recommend any other additives be added to the cooling system. Purified or distilled water mixed with the approved coolant/anti-freeze is the only protection approved by YANMAR. Concentrations of the Enix-ture should follow the recommendations of the manufacturer. The coolant/anti-freeze must be compatible with aluminum. The coolant/anti-freezes that have been tested and approved are shown below:

• Texaco Long Life Coolant Anti-Freeze both regular and pre-mixed Product codes 7991 and 7998. This product is available in gallon containers, drums and bulk. It is recommended that the cooling system be drained and flushed before filling. Only Texaco Long Life Coolant should be used for top-off. This product has a much longer shelf life than conventional coolants provided the integrity of the container is maintained. For additional information and availability contact Texaco at 1-800-782-7852.
• Havoline Extended Life Anti-Freeze/Coolant. Product code 7994. This product is available through Texaco gas stations, Procedures are the same as with Texaco Long Life Coolant Anti-Freeze.
• Dex-Cool Long Life Coolant. This product is available through GM service centers worldwide.
• Prestone Extended Life Coolant. Product code AF888. If the above coolants are not readily available, Prestone Extended life coolant is satisfactory.

While this seems a bit extreme when talking about 'extended life coolants' I suppose it guarantees the effectiveness of the coolant package. I don't change mine that often, but I do monitor the condition of the coolant, clarity, voltage and pH.

As to the uneven idle when first starting a cold engine, mine does it too. I just advance the throttle to 900-1000 for a minute or so until it warms a little and settles down. Mine does not have the fast idle control or intake air heater either. I think those are cold-climate accessories that do not come standard on base engines.

Larry
M/V Boomarang

 

[bayview]

The aluminum probably requires fresh anti corrosion inhibitors.


Un even idle after start might indicate a bit of fuel drain down due to a small air leak except maybe in cold climates.


Uneven firing of old gas engines was caused by gas not getting to or, some flooding, and not firing in all cylinders. Just loved listening to the sound of old rotary aircraft engine cylinders joining the party at start up.

 

[Nomad Willy]

Yes ,
The reason for the extended life AF is because of the aluminum parts exposed to the coolant. I talked w Yanmar about this.

If you're aluminum free you don't need ELAF. Haha but this is coming from a guy that says you don't need MV lube oil. I use the green stuff as there's no aluminum on my engine or in the cooling system.

 

[bshillam]

Another question,
So the engine has only 800 hours on the meter. I notice when started that it smokes a little until completely warmed. Is this usual for the smaller marine diesels?

 

[LarryM]

Another question,
So the engine has only 800 hours on the meter. I notice when started that it smokes a little until completely warmed. Is this usual for the smaller marine diesels?

I have the exact same engine and it is completely normal. You will find a pretty good discussion here on the proper operation of these engines. Mine runs cleaner after a hard run than after prolonged slow operation. Its just the nature of the beast. Make sure to run it hard enough to keep the cylinder bores from glazing.

 

[FF]

Depending on the construction , weather the cylinders are exposed to coolant or stuck in a sleeve may be the reason for the yearly anti freez change.

In larger engines with exposed to coolant cylinders a SCA additive is required to be installed , measured with strips and maintained at the correct level.

Loads easier to say , dump it , than explain the proper drill for maintaining a modern engine

 

[bayview]

I would not use any cooling flush not specifically recommended by the maker. Aluminum, iron and rubber all together can do weird things in the presence of acidic solutions.


Do check the exhaust install to be certain that the water mixing area cant drain back into the engine. This installation failure is not uncommon.

 

[Nomad Willy]

My small (37hp) Mitsu smokes at startup so little you've got to look hard to see it. And only for a minute or so. No amount of throttle will produce smoke when warm. The engine is a 3000rpm engine propped to 3050.

 

[LarryM]

My small (37hp) Mitsu smokes at startup so little you've got to look hard to see it. And only for a minute or so. No amount of throttle will produce smoke when warm. The engine is a 3000rpm engine propped to 3050.

Same here, no smoke when warm at any speed, including WOT. This is a 3800rpm engine and is propped to 3900 with a clean bottom and half load.

BTW, according to Laborde Products, the Yanmar distributor for the Gulf Coast: "Use white vinegar 3:1 with water to clean the raw-water side of HE. Let it circulate for 4-6 hours. It is gentle and effective."

 

[Ski in NC]

One of the biggest killers of marine engines is corrosion from deck hatch drips or even condensation. In my area, we get warm fronts after cold fronts, and engines chilled in the cold sweat like a cold beer when a warm front comes in. That sweat will cause a lot of damage over time. Hatch drips are self explanatory, and are often salt water, even worse.

Block heaters solve the condensation problem, but running all the time is expensive and wasteful.

Block heaters are often sized for starting engines in arctic conditions, and are overkill for this purpose. Only a couple hundred watts will keep block above dewpoint, which does the trick.

On my personal boat, when a warm front is expected, I go down and crank the engine and gen to warm them up. Then no condensation when the warm damp air arrives.

Not sure if you west coasters have the same issues.

Keep them dry!!!

 

[FF]

The bad corrosion is inside the cylinders when the go thru the same climate hassle .

Engine fogging as well as sealing the intake and exhaust as done on winter layup would work , but are a PIA.

I have often thought a fogging setup could be push button before shutdown with a bit of inventiveness.

Just tell your dock mates its mosquito control.

Advantage gas engines , the choke and throttle plate keep much of the breeze from blowing thru the engine 24/7

 

[Pgitug]

We just sold our sailboat that has a Yanmar 4JH4E 54 hp diesel. It was a 2005 with 3700 hours when we sold it last November. The engine ran really well for us. The only frustrating issue I had was a rising operating temperature reading over time. The short version is that the fresh water/antifreeze side of the cooling core had a "Clay" like build up on the cooling rods which insulated the heat transfer. The remedy was to use a NAPA brand radiator flush. After following the instructions the coolant came out looking like coffee. After that I could run at WOT, 3200 for this engine, and the temp would sit at 178 degrees just like when she was new.
The only caution I would give is the exhaust elbow. Ours was not stainless steel but rather the more expensive cast elbow. When the boat sat for a month or more we always flushed the raw water side with fresh water for five minutes and then shut the engine down. Even with the flushing we found that we needed to change out the exhaust elbow at 1400 hours or the corrosion would be thru the interior sleeve.
Yanmar recommends changing oil every 200 hours. We changed ours every 100. Oil is cheap.

 

[BruceK]

We just sold our sailboat that has a Yanmar 4JH4E 54 hp diesel. It was a 2005 with 3700 hours when we sold it last.
The only caution I would give is the exhaust elbow. Ours was not stainless steel but rather the more expensive cast elbow.... Even with the flushing we found that we needed to change out the exhaust elbow at 1400 hours or the corrosion would be thru the interior sleeve.

That may in fact be a reasonable life. My insurer wants elbows removed and inspected every 5 years, I guess that has to come from experience. How old were yours @1400 hours? Maybe your careful maintenance extended its life.
I`d have hoped ss would last longer than cast iron, and expected it to cost more. I looked at getting them made in ss (for Ford Lehmans), it was much cheaper importing cast replacements.

 

[Al]

Larry M- Could you expound more on the use of vinegar? How do you circulate and recover in a "Raw Water" application? My raw water ex's out the exbaust. It would seem more productive to be cleaning out the closed system. Wrong?

Thanks,
Al

 

[LarryM]

Larry M- Could you expound more on the use of vinegar? How do you circulate and recover in a "Raw Water" application? My raw water ex's out the exbaust. It would seem more productive to be cleaning out the closed system. Wrong?

Thanks,
Al

Al,

It is pretty easy and works on almost any size fresh-water cooled marine engine. I use a 5 gal plastic pail and a Jabsco Water Puppy pump. The pump has standard male hose connections on the inlet and outlet so you can use garden hose and plastic hose reducers/couplers to make the connections to the engine hoses. If also changing the raw water impeller, first close the seacock, remove the impeller and replace the cover. That way, you can make one connection on the seacock side of the water strainer. The other connection is to the heat exchanger outlet to the mixer elbow. Drain the raw water system using the pump or gravity. Next fill the plastic pail with vinegar or flushing solution and use the pump occasionally to circulate the mixture through the system. Start by back-flushing to remove any loose materials from the heat exchanger. Half way through the process, reverse the hoses and circulate in the original flow direction. Finally flush with fresh water using a regular water hose. You should now have a clean water strainer, raw water pump housing and heat exchanger. Reconnect the original hoses and don't forget to replace the impeller and open the seacock before starting the engine. If you are not replacing the impeller, make the flush connection directly to the inlet side of the heat exchanger. You can use the same rig and method to flush A/C coils too.

 

[FF]

Even engines with glow plugs will smoke a bit at start up.

A compression ignition diesel will smoke from poor or incomplete combustion caused by the cool engine.

The inside of the combustion chamber , head , piston and cylinder temperatures cause the fuel sprayed in as tiny dropplets by the injector to vaporise , then ignite.

Untill all this metal gets to a minimum temperature , some smoke is to be expected.

On old engines where compression is suspect , watching the coolant temperature to see a when the exhaust is clear will give an estimate on how shot the engine is.

If it still smokes at 180F , beware!

 

[LarryM]

Larry M- It would seem more productive to be cleaning out the closed system. Wrong?

Thanks,
Al

Al,

Both the closed and raw water side of the system must be clean in order for the engine to be properly cooled. Over the years, I have found the raw water side requires more maintenance for a variety of reasons.

As for the closed system, if it is clean and the coolant has been changed regularly, annually in the case of Yanmars, they don't seem to require much additional cleaning. If, however, there has been neglect or changing of coolant types, and you find a build up of scale or deposits that prevent normal heat transfer, you will want to use a flushing/cleaning agent and re-fill with the proper coolant. You can use Prestone radiator flush which is safe for mixed metallurgy cooling systems, or use a professional two-part product. Once clean, they only need to be drained, flushed with clear water and re-filled with the correct coolant. Yanmar Technical Bulletin MSB 02-051 has the guidelines for the coolant and change interval.

 

[Al]

Thanks Larry.

The inquiry was made in the vain of all of my many years owning and operating boats the question or need to address the raw water system revolved around clogged elbow and most of those were raw water cooling engines. Yes, closed system with raw water for gear and exhaust also suffered clogging it just seems more on gasoline engines in the fleet,than diesel. Not so much conversation among owners of diesel power.
Why that is maybe relevant to your solution and explanation. I wonder- would the condition of the local waters have an effect on the systems requiring more attention say in Texas over the cooler waters of Alaska?
That is presented on the basis of having never paid any serious attention other than rare changing out said exhaust elbows and replace impellers.
On the closed side, flushing is more of a common event but not something done on an annual basis more on a awareness of a coming failure. This at least is my knowledge among the boaters known to myself.

Interesting process Larry and not something to look forward to having to do, rather a "Damn! Time to flush" chore.

Regards
Al