Repower 1978 Hunter 30 - Ysm12 to 2YM15

dLj

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Mar 23, 2017
3,374
Belliure 41 Sailing back to the Chesapeake
For any of you interested in also making these modifications I found this amazing write up of someone installing a brand new beta on their boat. modifying engine beds – ¡Viva San Patricio!

Only thing I’m confused about is how he went about installing the 3” lag screws. Epoxy them before inserting it into the new bed? Worried how they will hold over time and if water might leak into the wooden core.
This is quite a good write-up of putting in a new engine. I've put a few in and will say, I've never yet seen a replacement engine that did not need some kind of changes to the bed...

dj
 
May 27, 2004
1,964
Hunter 30_74-83 Ponce Inlet FL
Here are a couple of pics of my 2GM20 install showing the rails I mentioned
.20201114_104101.jpg20201114_104113.jpg
 
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May 27, 2004
1,964
Hunter 30_74-83 Ponce Inlet FL
No cracking or movement in the past 7 years.
I suppose you could get a machine shop to make them out of aluminum bar stock.
 
Dec 28, 2015
1,837
Laser, Hunter H30 Cherubini Tacoma
I have the same 2gm20f in my 78 that was a reposed by the prior owner. Mine has aluminum angle stock in the same configuration. It will do 6.5 at 3400rpm. It has a 3 blade fixed prop that I don’t know the specs.
 
Oct 26, 2008
6,046
Catalina 320 Barnegat, NJ
I swapped my 1GM for the 2YM15. I didn't do the work myself but I did verify the dimensions before deciding to proceed. The width was a perfect match (right down to the same mm). The length was 2 inches longer, which was easily accommodated on the stringers. I had no problem with clearance above or below. I did have to bump out the face of the engine compartment because there was no clearance to slide the engine back the 2 inches. Of course your existing footprint is different but you can easily verify based on the listed footprint dimensions. You will never be sorry about trading your engine for a new, reliable engine. I figured that I could do the job, but the learning curve would be too steep and time consuming, much more than I wanted to bite off. It cost a lot to have a certified installer do the job, but you want it guaranteed, right? My advise would be to pay for the installation and never look back. (But stay involved and watchful if you have any question)
 
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