Choosing an inboard engine to fix up

[brlfc1969]

Hello,

I am looking to buy a small inboard marine engine (up to say 25 hp) that needs doing up, so I can learn as I do it.
I would like to know what members think is a simple engine for such a task, availability and cost of parts etc. Intention is not to try and make any money on rebuilding an engine, but to learn how it works and how to repair it.

Thanks in advance.

 

[Tranona]

Really would not bother. almost nobody rebuilds modern small marine diesels. Essentially they never wear out but die from lack of use or the marinising bits fail and are uneconomic to repair as parts are generally very expensive or with older engines unobtainable. There maybe some value as a learning exercise in getting a running engine, taking it apart and getting it running again, but not sure what you would learn or how you would apply that newfound knowledge.

 

[fredrussell]

Whilst I agree with Tranona I see no harm in getting a cheap old donk in the shed and pulling it apart for a fettle. Perhaps best off with a Beta engine as there seems to be a feeling - on here at least - that Beta/Kubota parts are cheaper and perhaps a bit more available.

 

[Trident]

The best engines are Yanmar but the parts are costly . Beta Marine use Kubota lumps and this most of the spares are cheap because they are also used on diggers etc all over the world. Beta also have a lot of information and documentation available - give them the serial number even after 20 years and they have full specs of that engine, any customs changes (like upgraded alternators etc ) and even photos from the factory before they left. The down side is things like the heat exchanger are almost service parts as they rot quickly

To some degree, if it suits your use when done , a raw water cooled engine will be simpler - fewer parts to worry about, but also more likely to degrade from all that hot seawater going through the block. Very little is simpler than a Yanmar 1GM or 2GM (10 hp or 20 hp) but if you prefer fresh water cooled the stick to Beta (Nani also use the same engine from Kubota but are not UK based like Beta and not as helpful by phone)

 

[Poignard]

The single cylinder BUKH DV10 is a simple engine to overhaul and will last a long time if you have done the work carefully.

All parts are available but are expensive.

 

[Snowgoose-1]

Really would not bother. almost nobody rebuilds modern small marine diesels.

It's the age we live in.
I can remember in my youth taking things for my mother to the "menders". When I went shopping for her, there was the shopping bag. Everything went in loose, bread, fruit and veg the lot.
Without knowing it , we must have been Eco Warriors.

 

[ridgy]

Very reasonably priced rebuild kits available for yanmars.
E.g. Yanmar 2GM20 Engine Overhaul Kit

I've thought about doing the same thing and having a spare engine ready to go. Would be very satisfying. My current engine is.nearly 40 years old but runs far too well to risk tinkering.

 

[Tranona]

It's the age we live in.

And all the better for it. Little diesels will run for 8000 hours if properly looked after. coastal cruising yachts typically do around 100 hours a year. Likewise modern car engines outlast cars whereas in my yunger days engines might make 50000 miles, but fortunately the cars they were in would likely have rusted away by then!

 

[Minerva]

I would recommend a bmc1500 block. Often marinaded and rebadged as Thornycroft. Parts are readily available and pretty cheap too from ASAP supplies.

 

[Poignard]

...

 

[PaulRainbow]

Rebuilding an old small engine because your existing engine is a spectacular waste of money in most cases. Rebuilding one just for practice is an even greater waste of money, you end up with something that cost a lot and is worth next to nothing (if you're lucky).

Not sure what you will learn alone the way, but i'm certain that almost anything you learn will never be of real use. You'll never want to rebuild one for real.

If you want to learn how to keep a marine engine running in the real World you need to learn how to fix external stuff on the fly (at sea) and how to deal with things like routine servicing, fuel blockages, failed impellers etc etc.

 

[Buck Turgidson]

If you learn how to get seized pencil annodes out of a 2q15 let me know please!

 

[Poignard]

If you learn how to get seized pencil annodes out of a 2q15 let me know please!

I know how to avoid that on a BUKH DV10.

Reduce the diameter by 3mm before inserting them.

 

[ridgy]

If you learn how to get seized pencil annodes out of a 2q15 let me know please!

Do you mean you can unscrew the plug leaving the anode stuck in?

I've heard that pumping Rydlyme round the cooling circuit will get rid of anodes soon enough. With the plug out you can sit and watch it happen.

 

[wombat88]

The problem with inboard engine '''projects''' is cooling. OK so you can run the engine on your garage floor with pipes and buckets but cooling the exhaust is another matter.

Then...there are the neighbours to consider. A 'wet' exhaust does not really work with a silencer from a Ford Fiesta...this I know from experience.

In the last few years I have done a couple of Petters and Vire, just for the hell of it. They came free and costs were almost zero apart from a trip to the local breakers for rubber hoses.

I am over this now.

 

[Buck Turgidson]

Do you mean you can unscrew the plug leaving the anode stuck in?

I've heard that pumping Rydlyme round the cooling circuit will get rid of anodes soon enough. With the plug out you can sit and watch it happen.

No the plugs (there are two) were over torqued by some muppet ( me) two years ago and now no reasonable amount of percussive engineering will get them to budge!

 

[Refueler]

Rebuilding an old small engine because your existing engine is a spectacular waste of money in most cases. Rebuilding one just for practice is an even greater waste of money, you end up with something that cost a lot and is worth next to nothing (if you're lucky).

Not sure what you will learn alone the way, but i'm certain that almost anything you learn will never be of real use. You'll never want to rebuild one for real.

If you want to learn how to keep a marine engine running in the real World you need to learn how to fix external stuff on the fly (at sea) and how to deal with things like routine servicing, fuel blockages, failed impellers etc etc.

Pal of mine with a 1YME Yanmar has gone through that pain ...

Bought the 31 with a 'tired' YME .. as a tinkerer - I've lost count of the cars he's felt needed his attention !!

First it was lack of compression ... then it was the small lift pump - very strange item !! - he couldn't get that pump to work ever again !!

He replaced the pump .. worked on the engine ... but it was still a lazy hard to start lump. He found a 2nd hand engine - had it delivered ... then went through the pain of extracting the old and fitting the replacement - typical boat - its as if the fitted engine - then put boat together !

That replacement engine ? Started ok .. ran ok ... but of course not well enough for him ... tinker tinker .. now he has an engine that I am not so confident about .. he reckons he's improved ... mmmmmmm

He always remarks about my Perkins 4-107 ... looks like a lump of s*** ... but starts and purrs along as if it came out of factory yesterday .. As I say to him .. I leave it alone ... I don't tinker with it ... I only fix / do what is absolutely needed.

The 2GM in my other boat ... I have same system with that - LEAVE IT ALONE !! It purrs along all day ...

I commend OP for his idea - but in practical reality ? What is the end result ? What is learnt ? Maybe a RYA Diesel Course can be more benefit ?

 

[Tillana]

The canal and river trust do an engine maintenance course which I found very helpful when I was learning about my engine. I recently pulled a Kubota out of a skip at work for the exact same reason. Familiarising myself with my new beta and to strip for spare parts

 

[Poignard]

Hello,

I am looking to buy a small inboard marine engine (up to say 25 hp) that needs doing up, so I can learn as I do it.
I would like to know what members think is a simple engine for such a task, availability and cost of parts etc. Intention is not to try and make any money on rebuilding an engine, but to learn how it works and how to repair it.

Thanks in advance.

Good idea.

You'll enjoy doing it and learn as you go.

 

[fredrussell]

.. I leave it alone ... I don't tinker with it ... I only fix / do what is absolutely needed.

The 2GM in my other boat ... I have same system with that - LEAVE IT ALONE !! It purrs along all day ...

I commend OP for his idea - but in practical reality ? What is the end result ? What is learnt ? Maybe a RYA Diesel Course can be more benefit ?

Agree completely- my 3GM looks like it’s been brought up from the Titanic but runs beautifully and apart from servicing is left well alone. But I think OP has a curious nature and can see why he or she might find it interesting to pull an engine apart and rebuild it.