# Bukh engines



## GBurton (Jun 26, 2007)

The boat I just bought came with brand new Bukh engine. (Not installed)
Does anybody have experience with these engines? I know that they are used as lifeboat engines and are specifically built for marine use (not marinised automotive)

It is very heavy and appears to be well built.


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## Tartan34C (Nov 21, 2006)

I have some but only very, and I mean very basic experience with small ones. What do you need to know?
All the best,
Robert Gainer


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## GBurton (Jun 26, 2007)

How hard is it to get parts - and how reliable are they?

This is a DV 24 (24 HP)


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## Tartan34C (Nov 21, 2006)

They have been very reliable in my limited experience but parts are a problem. It is a current production engine so you can order any parts you need but I don’t think you will find any stocking dealers in the US. By the way you will only get 19 to 20 usable horsepower from that engine and for a heavy boat it might be a tad light in the power department. I don’t have a need for lots of power and my engine is small by popular standards but you are going even smaller in terms of HP per pound of boat.
All the best,
Robert Gainer


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## Jeff_H (Feb 26, 2000)

I had the small, single cylinder Buhk (10 hp) in my Laser 28. I really liked the engine, it was reliable and very easy to work on. Most of the parts were reasonably priced, and parts were generally in stock or a few days away and advice was readily available from a local dealer (Davis Craven at Waterway Diesel) and from online Dealers. It did have a few minor oil leak issues, in that it was hard to assemble the waterpump/fuel lift pump assembly without getting leaks. The only other problem that I encountered was that the steel frame that supports the engine and which comes with the saildrive package fatigued and broke dropping the engine into the bilge. I was able to temporarily support the engine, and remove the steel frame. When I got the frame out I felt that it was poorly engineered and so re-engineered it when I had it repaired. 

Their saildrive was very nicely engineered as saildrives go, but it could only use a particular model Gori propellor, and I personally would not have another Gori prop on a bet. I found this prop to be pure junk, and Gori to have a antagonistic attitude if you had a problem, providing worse than lousy service for thier products in North American.

Jeff


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## GBurton (Jun 26, 2007)

Is there a recommendation for HP/LBS of boat?



Tartan34C said:


> They have been very reliable in my limited experience but parts are a problem. It is a current production engine so you can order any parts you need but I don't think you will find any stocking dealers in the US. By the way you will only get 19 to 20 usable horsepower from that engine and for a heavy boat it might be a tad light in the power department. I don't have a need for lots of power and my engine is small by popular standards but you are going even smaller in terms of HP per pound of boat.
> All the best,
> Robert Gainer


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## TSOJOURNER (Dec 16, 1999)

Ive got a 1977 DV20 that came with my Pearson 36. It wasnt installed and still isnt. From what the last owners said, the motor was great and never gave any problems, but the gearbox gave out. If i would find another gearbox, i would put the motor back in my boat. Its got a ZF gearbox. Ive got all the parts to it somewhere.


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## AjariBonten (Sep 7, 2007)

GBurton said:


> Is there a recommendation for HP/LBS of boat?


Everything I've read seems to indicate 2 HP per 1,000 pounds of displacement as the common formula.

Fred


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## timebandit (Sep 18, 2002)

SVDistantStar said:


> Ive got a 1977 DV20 that came with my Pearson 36. It wasnt installed and still isnt. From what the last owners said, the motor was great and never gave any problems, but the gearbox gave out. If i would find another gearbox, i would put the motor back in my boat. Its got a ZF gearbox. Ive got all the parts to it somewhere.


You might try here for gear box parts.
http://www.pjpower.com/sales/


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## tdw (Oct 2, 2006)

Raven came with a DV24, originally installed 1991. The only real problem I have had with the thing is that it leaked oil out of the main sump. This turned out to be a poorly installed line for draining the oil and although it took some time to track down the problem once we did so it was easily fixed. 

We also had a problem with oil coming out the exhaust. It appears that this was caused by excess fuel not lubricating oil. I'm not a mechanical whizz OK , but somehow it was do with fuel pumping through the system on shutdown. It was solved by making sure we always kill donk with engine at idle. With our previous boat shutting down while engine was revving at over idling speed was not a problem. The Bukh apparently doesn't like it. (No I don't mean shutting down engine at 2500 revs. I'm talking about only a few hundred revs over idle.)

Previous boat had a Volvo Penta . Compared to the Volvo the Bukh is quieter but uses a lot more juice than the Volvo. At first this concerned me greatly until I realised that because it is comparatively quiet we use the thing a lot more than on PB. 

The other thing I do like about the Bukh is that it's about as big (I think) as you can go and still hand start when necessary. 

All in all no serious complaints although I'm told that a three cylinder would be quieter still. ??? To date parts have not been a problem but then Bukh have an official distributor in Oz. I'm told that parts are a problem in SE Asia or Pacific region. No problem in Europe.


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## Rockter (Sep 11, 2006)

I understand that they are Swedish. I have seen one of them, a twin. It looked well-built, but probably with expensive spare parts. 
The triple will be inherently better balanced than the twin. Triples are polular on motorcycles for that reason.


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## Tartan34C (Nov 21, 2006)

​


GBurton said:


> Is there a recommendation for HP/LBS of boat?


Like most quick rules of thumb this number, pounds per HP needs some common sense to use effectively. The amount of horsepower expressed this way varies quite a bit with length. And surprisingly it decreases as the boat gets larger. The best way to look at it is compare similar boats and in your case compare to other Westsails 32's.

If you want the base numbers to draw a chart start with,
500 pounds per HP equals a speed length ratio of 1.3
1,000 pounds per HP equals a speed length ratio of 1.05
1,500 pounds per HP equals a speed length ratio of .95
2,000 pounds per HP equals a speed length ratio of .85

If you select 2 HP per 1,000 or 1 HP per 500 pounds you can expect a speed length ration of 1.3 which is high for a Westsail 32 but let's go with that number and work it out, so with a waterline length of 27.5 feet you can expect a speed of 6.8 knots. This is all based on shaft horsepower not advertised power.
All the best,
Robert Gainer


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## Rockter (Sep 11, 2006)

Robert...

What am I misunderstanding? 

How does one get a figure of 6.8 from the two figures 27.5 and 1.3 ?

My ship weighs 23,000 lbf, and I have about 35 hp (Volvo say). What speed should I expect? The ship is a double-ender... a Union 36.... with a big footprint in the water and a wetted length of 33 ft, apparently.


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## JimsCAL (May 23, 2007)

I am sure Robert (as a Naval Architect) can explain this much better than I can (being a Marine Engineer), but I suspect he calculated the hull speed using an equation like:

Hull Speed (kts) = 1.3 to 1.4 X Square Roof of Waterline Length (in feet)

Hull speed in a displacement (non-planing) hull is when the resistance due to wavemaking basically limits further speed increases. Below that speed, the frictional resistance dominates. The very rough rule of 2 Hp per 1000 lbs generally provides sufficient power to get to hull speed plus a little margin.


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## Rockter (Sep 11, 2006)

OK, so it's 1.3 (say) times the square root of waterline length.

I got it.


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## JomsViking (Apr 28, 2007)

Rockter said:


> I understand that they are Swedish. I have seen one of them, a twin. It looked well-built, but probably with expensive spare parts.
> The triple will be inherently better balanced than the twin. Triples are polular on motorcycles for that reason.


They are Danish, not Swedish. And due to rotating counterweights they do not vibrate much. I have a new (2004) DV24ME and really love it compared to the Volvo's and Yanmar's I've seen. But I've only owned boats with Volvo's (and no engines) before. One of my friends installs these in rescue boats WW and is VERY proud of the product, which was one of the reasons for me to choose that engine (having your own mechanic is also great  )


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## GBurton (Jun 26, 2007)

I have found out that Bukh sells a turbocharger for the DV24 (The engine that I have) This might solve the problem that I have with the engine being too small for my boat (Westsail 32)

What are the pros and cons of turbocharging a sailboat engine?



JomsViking said:


> They are Danish, not Swedish. And due to rotating counterweights they do not vibrate much. I have a new (2004) DV24ME and really love it compared to the Volvo's and Yanmar's I've seen. But I've only owned boats with Volvo's (and no engines) before. One of my friends installs these in rescue boats WW and is VERY proud of the product, which was one of the reasons for me to choose that engine (having your own mechanic is also great  )


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## Tartan34C (Nov 21, 2006)

GBurton said:


> I have found out that Bukh sells a turbocharger for the DV24 (The engine that I have) This might solve the problem that I have with the engine being too small for my boat (Westsail 32)
> 
> What are the pros and cons of turbocharging a sailboat engine?


The downside is shorter engine life and more likelihood of unexpended failure. I don't feel the need for very much power on a sailboat and in fact sometimes sail without an engine of any kind. Maybe you should try the boat before changing things. 
All the best,
Robert Gainer
.


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## GBurton (Jun 26, 2007)

The thing is that the engine is not installed. I have to make the decision on whether to install the engine or not.


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## tdw (Oct 2, 2006)

GBurton said:


> The thing is that the engine is not installed. I have to make the decision on whether to install the engine or not.


What's you displacement ?

Raven is 34' displaces about 8 tons in the old imperial scale, 7 tonnes metric.

Relatively easily driven hull, fin keel.

Our Bukh DV24 is quite sufficient for our needs. Yeah, maybe I'd go up in size if buying a new one but its basically cool as. No turbo. We run a three bladed fixed prop btw. Would prefer folding but can't be bothered to pay the dosh.


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## GBurton (Jun 26, 2007)

21 000 lbs


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## Tartan34C (Nov 21, 2006)

GBurton said:


> I have to make the decision on whether to install the engine or not.


You're on your own with that one. I don't know what type of person you are and besides you don't even know how you want to sail. Some people are content to do without an engine entirely and others want a motorsailor with lots of power. Your engine is small compared to what the average owner has on the average boat and that's the only fact in the equation. Everything else is an opinion.

I elected to only put 20 horsepower in my Tartan 34C and by today's standard that's underpowered and your boat is much heaver then mine. I sail my boats and only have an engine to move in the marinas and crowded harbors. In fact I have owned unpowered boats most of my life and have crossed oceans on unpowered boats. I take pride in the fact I can sail and don't need to keep to a schedule. The only advice I can give is to point out that by selecting an average size engine you will be among the averaged group of owners with an average boat and you will be just as happy as the average owner. If you install a small engine you will reduce the value of the boat when you sell her and put your self into a situation where skill and planning must replace muscle and brute force.

By the way, a turbocharger adds power at the top end of the RPM's and to push a sailboat you are better to have the necessary power at a lower point in the power curve. A turbocharger is better suited to a powerboat where the engine is run at a higher RPM. On a sailboat a slower turning larger diameter propeller is better then a smaller faster turning propeller.
Good luck and all the best,
Robert Gainer


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## GBurton (Jun 26, 2007)

You're correct there Robert......the engine is small for the average user and I have to say that I'm no Bertie Reed.


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## tdw (Oct 2, 2006)

GBurton said:


> 21 000 lbs


Heavy !!

In theory I'm with T34 on this one in that I like to have the smallest engine possible. Saves on weight, saves on fuel (within reason), with luck can be hand started.

Against this are our local conditions. My preferred sailing area is outside the harbour but we are moored a fair way up stream. To sail from our mooring to the heads can be a strain dodging ferries, racing fleets, tankers, liners and morons in stinkers. Was easy 20 years back, now too crowded so we tend to motor until we are in sight of the heads.

Outside, I'd rather potter along at one or two knots than run the engine.


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## Rockter (Sep 11, 2006)

My own ship is a 23,000 lb double-ender with a long keel. A 35 hp motor moves it well with a two blade prop. It's a heavy motor, close to 780 lb.


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## haffiman37 (Jun 4, 2004)

In this application torque, as in most sailboats, will be the main issue One thing is engine torque, another and most important is prop-shaft torque, in other words gearbox ratio and what prop it may handle.
The DV24 has a torque of about 55Nm in rpm range 1800-2400 and is delivered with either 2,5 or 3:1 gear box. That will give roughly 137,5 - 165 on the shaft.
If we compare to Yanmar 3YM20 and 3YM30 the figures will be:
3YM20 (21hp) 51Nm in range 2000 - 2600. Gearboxes:2.21,2,62,3,22:1.
121,5 -133,62 - 164.22Nm on prop shaft.
3YM30 (29Hp) 70Nm 2000 - 2500rpm, same gearboxes as above.
154,7 -183,40 - 225,4Nm.
My answer in this case would be if the attaced gearbox is 3:1, install it, You will probably have enough torqe and 'power'.
I have a 3GM Yanmar with a 2.62 gearbox, cruising wheight of 8000 kg (16000lbs) and run a 3-blade Flex-O-Fold prop. Top speed 7knots+, cruising 5kn at 2000rpm, in a Jeanneau SO37 -2002.


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## GBurton (Jun 26, 2007)

I sold the Bukh and bought a Betamarine 39 hp. It is very pretty


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## Rockter (Sep 11, 2006)

The Kubota-based Betamarine.
Should be a good unit.
They cannot rip you off for parts like Volvo try to.


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## JohnRPollard (Mar 26, 2007)

GBURTON,

Good call. Is that the BV1505? That's a fairly large engine, but it will be nice having 4 cylinders pushing that Westsail. I think you made the right decision, all things considered. 

I like what I've learned so far about them while studying these Beta engines. I'd be interested to hear installation and performance reports when you have them.


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## Rockter (Sep 11, 2006)

It's the long-serving Kubota motor.
They have been around a while, so there will be plenty of bits around for them that were used for fork-lifts, generators, and so on.
This is so important in the long term, as the engine supplier cannot charge too much for the parts, as others, Volvo being the worst for me, try to.
If Betamarine try that one on, just find the bit that's broken from a fork-lift supplier, or similar.
The exception will be the marinesed bits, but do they fail often? I wonder.


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## sctpc (Jun 23, 2008)

I know this is an old Thread but Im very concerned,
I have a Bukh 10hp and yesterday I got caught in a squall on port Phillip bay and tried to run her at 2700rpm and could only get 2200rpm and oil, fuel was coming out the exhaust, its like she has no power. Starts fine, idles but puts out black stuff and I cant get up the revs. suggested adjusting stop solenoid what do you guys recon is it a major problem and should I get a mechanic to look $$$ or be tight and run it till something happens!!! I do prefer option 1 but would like to have an idea first.


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## haffiman37 (Jun 4, 2004)

Check that your prop and boat bottom is clean!
Most likely unburnt fuel due to overloaded engine.


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## mitiempo (Sep 19, 2008)

If the prop and bottom are clean suspect the exhaust elbow. The exhaust is as important as the intake and if restricted by carbon build-up, which is common, the engine will do exactly as yours does.


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## sctpc (Jun 23, 2008)

Thanks Guys That would be it I dident check the prop or bottom this week as in two weeks im anti fowling it, and I haven't used it for 3 week ether.


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