Which diesel for cruising, Yanmar or Kubota?

[windshadow]

If I were to repower, i think I would go with the beta. i did a repower with a yanmar on my pearson35 a few years back.I had a break down do to a water lock it had to be rebuilt. i had to waite for one part for three weeks. I have looked into the beta a few mounths back for my nebe28 I think they make great engines based on my reaserch and talks I had with them on the phone I think there support is very good. hope this helps bill.

[Attwood]

You cannot go wrong with yanmar. Not only because of the world wide parts avalability but also because yanmar is very mechanic/maintenance friendly meaning very servicable and easy to work on.

[barboak]

Have a beta 50 we installed 5 years ago and have been in the Caribbean since and there is no issue with obtaining parts. You will find filters, belts etc. from auto parts stores everywhere and we carry a few spares such as water pump">raw water pump and air filter with us. Every Beta diesel owner we met, quite a few actually, is in love with their engine! Considered a Yanmar and so glad we did not as I strongly believe the Beta is a better block than the lightweight Yanmars

[Capex]

Originally Posted by barboak

Have a beta 50 we installed 5 years ago and have been in the Caribbean since and there is no issue with obtaining parts. You will find filters, belts etc. from auto parts stores everywhere and we carry a few spares such as raw water pump and air filter with us. Every Beta diesel owner we met, quite a few actually, is in love with their engine! Considered a Yanmar and so glad we did not as I strongly believe the Beta is a better block than the lightweight Yanmars

While you may have available parts in the Caribbean, that does not hold true for the rest of the world and Asia in particular.
The Yanmar small craft engine is their own design and they have been making Marine Engines (not converted car, truck or tractor engines) for over 100 years.
The larger engines in the 4JH and 6BY range use blocks from Toyota, Isuzu and BMW that are highly successful as are the originals.
I have seen Yanmar 3GM engines with up to 8,000 hours and 4JH with up to 12,000 hours before having a major overhaul! Try that with the Beta.

[barboak]

Originally Posted by Capex

While you may have available parts in the Caribbean, that does not hold true for the rest of the world and Asia in particular.

The Yanmar small craft engine is their own design and they have been making Marine Engines (not converted car, truck or tractor engines) for over 100 years.

The larger engines in the 4JH and 6BY range use blocks from Toyota, Isuzu and BMW that are highly successful as are the originals.

I have seen Yanmar 3GM engines with up to 8,000 hours and 4JH with up to 12,000 hours before having a major overhaul! Try that with the Beta.

Sitting next to a boat here in St. Martin who is waiting for turbo parts for his Yanmar so from my 12 years in the Caribbean experience do not get a turbo. Not sure if I considered cruising in Asia when I was deciding but 5 years ago on this forum when I asked a similar question as the OP the clear majority favored Kuboto-Beta as likely having a longer happy life and have never regretted it.


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[FamilyVan]

I looked into replacing my Perkins a short while back. I decided in the end I was better off with what I had. Betas were much more affordable than Yanmars. Much much more affordable than Volvos.

I have my doubts about it being difficult to find parts in Asia- or anywhere. Kubota tractors and construction equipment are every where. The local boat yard may not carry parts, but you should be able to get parts from tractor suppliers.

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[travellerw]

Originally Posted by Capex

While you may have available parts in the Caribbean, that does not hold true for the rest of the world and Asia in particular.
The Yanmar small craft engine is their own design and they have been making Marine Engines (not converted car, truck or tractor engines) for over 100 years.
The larger engines in the 4JH and 6BY range use blocks from Toyota, Isuzu and BMW that are highly successful as are the originals.
I have seen Yanmar 3GM engines with up to 8,000 hours and 4JH with up to 12,000 hours before having a major overhaul! Try that with the Beta.

Thats very funny.. There are Kubota engines with 20,000 hours before a major overhaul. Granted the ones I heard about weren't used in a marine environment. Still, 20,000 hours in a tractor is a long time.

Longevity is not even a question. All the major engine manufactures produce and engine with a similar long lifespan.

[Yukon Cornelius]

Originally Posted by Capex

While you may have available parts in the Caribbean, that does not hold true for the rest of the world and Asia in particular.
The Yanmar small craft engine is their own design and they have been making Marine Engines (not converted car, truck or tractor engines) for over 100 years.
The larger engines in the 4JH and 6BY range use blocks from Toyota, Isuzu and BMW that are highly successful as are the originals.
I have seen Yanmar 3GM engines with up to 8,000 hours and 4JH with up to 12,000 hours before having a major overhaul! Try that with the Beta.

I don't think this is quite fair. I know of three different Yanmar 3GM's in my club that have had catastrophic failures, and all three engines had under 4000 hours. Conversely, I also know of several 3GM's that do in fact have over 7000 hours and still run great. I'm sure that Beta has a similar track record, good and bad. Sometimes it's poor maintenance, and sometimes it's just bad luck, but all things mechanical will fail eventually.

I think the best reason to repower with a Beta is customer service. They are in the business of repowering and seem to be very helpful, and understand the problems, special parts, and support needed. Yanmar is in the business of providing engines to new builders - good luck getting them to help you figure out how to fit a new 3YM on an Atomic-4 footprint.

Anecdotally, I repowered with a Volvo D1-30. The engine has been flawless (it's Perkins based, that's probably why). I wanted to try the Beta, but the Volvo was an easy fit in that particular application.

[Stu Jackson]

Another consideration is the mixing elbow. IIRC, the Yanmars have them kinda "built-in" as part of the exhaust riser (IIRC it's called the exhaust elbow). The Kubotas are external to the engine, where the exhaust gas pipe gets connected to the back of the manifold and the exhaust water is injected in a separate pipe nipple further down the line towards the water lift muffler. I have never heard of a Kubota exhaust riser getting plugged, whereas there have been numerous posts on this and other boating forums where the Yanmar assembly gets blocked. The Kubota failure point is almost always at the weld of the nipple, so it is a simple pipe replacement issue, rather than a manufactured part requirement. Thus, you can have it repaired anywhere you can find pipe (!), and could even use a T fitting for the injection point instead of a welded nipple. I'm just reporting the issue based on (a mere) 16 years of reading about these issues on this and other boating forums. I have a Kubota (Universal M25) and have replaced the exhaust riser on our boat after it was 17 years old (in 2003). If you do get a Yanmar and are going far afield, I suggest you purchase a spare exhaust elbow. They are both fine engines for their intended purpose, although there is great merit in parts pricing between the two. Availability is THE issue you'll need to figure out.

[Cheechako]

Originally Posted by Yukon Cornelius

I don't think this is quite fair. I know of three different Yanmar 3GM's in my club that have had catastrophic failures, and all three engines had under 4000 hours. Conversely, I also know of several 3GM's that do in fact have over 7000 hours and still run great. I'm sure that Beta has a similar track record, good and bad. Sometimes it's poor maintenance, and sometimes it's just bad luck, but all things mechanical will fail eventually.

I think the best reason to repower with a Beta is customer service. They are in the business of repowering and seem to be very helpful, and understand the problems, special parts, and support needed. Yanmar is in the business of providing engines to new builders - good luck getting them to help you figure out how to fit a new 3YM on an Atomic-4 footprint.

Anecdotally, I repowered with a Volvo D1-30. The engine has been flawless (it's Perkins based, that's probably why). I wanted to try the Beta, but the Volvo was an easy fit in that particular application.

Myself had two 3GM catastrophic failures one at 500 hours (complete replacement)and one at I think 2300 hours. (new pistons /rods)

[Jim Cate]

We have observed that in the South pacific there are indeed many ports sporting Yanmar signs. Unfortunately, these signs are often not accompanied by parts or knowledgeable staff. Once away from yachting centers, the myth of universal Yanmar parts availability breaks down, and their draconian parts supply system makes sourcing parts from other distant dealers difficult. We've heard a lot of woeful tales centered around this fact.

Our experience with a Nanni Kubota based 43 hp engine has generally been good, but their agents are not as helpful as the Beta folks who sell the same basic engines in many cases.

Jim

[Capex]

With regards to the OP, there is very little difference in longevity and reliability to either Yanmar or Kubota, from my experience.
The parts issue for ANY engine becomes luck of the draw in some of the remoter parts of Asia and the Pacific.
The issue of Yanmar engines with turbo charger (or any engine for that matter) is the fact that they are not operated correctly by the user. Diesel engines are made to WORK, unlike gasoline engines.Failure to put them under load will result in cylinder glazing. Failure to run a turbo fitted engine above 2,000 rpm will result in turbo failure. The reason for this is that the turbo will kick in at around 2,000 rpm and at this and greater speeds, the turbo shaft is properly lubricated. At RPM less than 2,000, the shaft is not properly lubricated and will wear out, causing severe problems.
So for those of you (and there are many from my experience) who "look after" your engines and never run them over 15-1800 rpm, you will have a glazing problem eventually and if fitted with a turbo - turbo failure.
Have you ever run your engine at WOT? (wide open throttle). you should occasionally.
Fair winds and happy sailing.