Todd, we repowered Impromptu with that same Yanmar.
It came with the motor mount base that made the swap easy.
If you want to really enjoy the swap, consider the Yanmar 3YM30 with the SD20 saildrive.
A 2 blade Flexo-Fold prop and you'll never look back.
It backs up straight, and was the best decision we've made in 30 years of ownership.
The background is, at one on the Newport boat shows, Rob Ball was doing booth duty at the Edson booth.
I asked him if there was anything he'd change if he did it over......he walked me to the next booth (Yanmar) and pointed to the 3YM30 set up with the sail drive.
The rest is history.
The fit was easy, and we ended up over 100lbs lighter.
A great choice.
Ron C.
On Jul 9, 2026 5:49 PM, William Coleman via CnC-List <[email protected]> wrote:
This fellow, I can't remember his name, sells Beta Marine diesels, they use Kubota engines.
He could tell you which one will fit into your boat.
https://www.soundmarinediesel.com/contact.shtml
Bill Coleman
Erie PA.
On 7/9/2026 5:27 PM, Todd Williams via CnC-List wrote:
It's time to replace my 46 year old Universal 5416 (Westerbeke M-20) in my 1980 C&C 34. Two oil leaks this season and a broken alternator tensioner bolt make motoring less than confident on the ocean. I searched the archives but did not see a thread about repowering.
JC Marine, here in New England, has many Yanmar 3YM-30, a newer and current production 20ish horsepower model. I can start doing the research but drawing on the wisdom of this wonderful group...
1 - Will a Yanmar 3YM-30 fit in the engine bay? Both through the stairway opening and when mounted.2 - Will the motor mounts line up?3 - Will the transmission line-up?
On the other option, is anyone interested in buying a 1980 C&C 34? It's a blue hulled, tiller model which I think is awesome when at anchor to get the full cockpit.
I hope everyone's having more fun than I am!
Todd R. WilliamsSaco, ME
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Bill
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