Motor swap

[ozmike]

I have a 3HMC 27hp yanmar, coupled to a SD20 saildrive, with head repair, new rings & bearings I am looking at $5,000. I have a chance to buy a 2006 RCD-3YM30X1 only done 50 hrs, was used to power a winch in a parasail boat, they are no longer in business and are stripping it back to a std boat, for $5,500 plus install, will it work with the SD20. What do you think my motor is old 10 yrs older than this, and my hour meter says 7,000. Bore still in good condition just needs a hone out.

[Ex-Calif]

Depends a bunch about the "plus install" part. Also depends on how much you want to spend. Some folks have a high tolerance for investing in the boat. Other considerations.

- Engine control panel
- Engine controls
- Engine mounting bed and engine mounts
- Exhaust system
- SD20 interface - Sorry I don't know if this engine is compatible.

You could be looking at a couple thousand or more for the swap over.

[ozmike]

But wouldn't a motor that's 11 years younger than mine be worth the investment, I am just not sure putting $5k into an old motor is a good idea, the next to go could be the starter motor or the alternator, all the extra parts are that old, but I do not have the $15k to put a new one in, oh what to do, I think I need another coffee or perhaps something stronger haha

[Ex-Calif]

Mike - That's the dilemma. You might need something stronger than coffee - LOL...

It is definitely a personal decision but my rules of thumb for "repower" include

- New engine will have higher HP - needed for power take off, clawing off lee shores etc
- Old engine parts are a rare metal - unobtanium (especially in remote cruising grounds)
- Old engine block or head or crankshaft or other key part is "trashed" and you need to source a major part
- Old engine is gasoline
- Old engine has a reputation of unreliability
- Some other major gripe about the old engine or some fantastic feature about the new engine

In regards to the accessories on the old engine - starter, injection pump, alternator. These are in some way "maintenance" items.

A properly overhauled "old" engine that has a good parts supply can be more reliable than an engine that is years younger.

The final thought is the boat ownership horizon - If I invest $8,000 in an overhaul will I keep the boat long enough to enjoy the return on investment. A $15k boat (like mine) isn't going to be worth $20k when I get my engine done (see my other thread about MD2010) - But I am keeping Relax Lah for some time to come and the utility of the diesel engine is very satisfying to me so the numbers make sense (at least to me - LOL)

Drink more coffee, spike with whiskey, get more opinions - enjoy whatever you decide to do!

[ozmike]

Thanks mate, I am hearing what you are saying, a new motor would be great, one with only 50 hrs is a compromise, but better than what I have, the only extra on install would be adapting new mounts etc. we are keeping "Manihiki" for the long haul, we bought her 4 yrs ago at a good price but now with the Aussie dollar stronger than the US, boat values have dropped dramatically over here, am going down to see mechanic now as he is a yanmar dealer and see if it will mate with the SD20, and get his opinion.

[Paul L]

A new YM30 with transmission and warranty is around US$7,200. So I'm not sure the 50 hr old one is that good a deal.

[ozmike]

They are about $12 k over here in oz, with a saildrive, but will have to wait till Monday , to ring up and find out what just a motor is worth.