Repower 1978 Hunter 30 - Ysm12 to 2YM15

Oct 28, 2018
27
Hunter 30 Cherubini Kemah, TX
When I purchased the boat (at great discount) the old yanmar Ysm12 would not start. After struggling with it for a while I got it to start. It’s still has issues, water not flowing out and temp buzzer going off (cleared buildup and need to reinstall everything and test it this weekend), slight oil leak that seems to be coming from where the starter meets the flywheel, and parts are increasingly difficult to find.

I plan on keeping this 1978 Hunter 30 years to come and made the decision that a repower would bring peace of mind and save countless hours of headache repairing the old Ysm12 (impresses this raw water cooled original engine just keeps going like the energizer bunny). Not looking to rebuild or repair the old engine. If the old yanmar lasted 40+years, I’m hoping I can keep the newer higher HP Engine going for at least half that time also.

Yanmar 2ym15 was quoted at around 6.5k and with a new harness, elbow, and panel, priced out at about 7.2k+ tax.

I’m a little shocked by the quotes I’m getting for the labor to swap them out. How difficult would it be to get the job done myself? If anyone has repowered their Ysm12, was the footprint different? What modifications were needed for the newer engine to align properly? Any advise on how to go about the repower is welcome
 
May 12, 2004
1,354
Hunter Cherubini 30 New Port Richey
Swapped out the old YSB12 with a new 3YM20 12 years ago. Pricey, but in my mind I was planning on keeping her for quite some time so I bit the bullet on that one and never regretted it. The footprint is a bit different. The mounting blocks (?) needed to be built in a bit as the new engine is a little narrower then the YSB.
 
Jul 7, 2004
8,058
Hunter 30T Cheney, KS
There are a couple articles of engine mods on your boat here at SBO. One sailor rebuilt his original. The other I can't tell. Since you want to keep her, and it's not my money, I recommend the upgrade. I have the smoother 18HP in my 30T.

Practical Sailor talks about the engine in their review of the Hunter 30. They say your engine is adequate, but as the Toolman says "it needs more power!". I hope you document the swap for other older H30 owners.
 
May 27, 2004
1,707
Hunter 30_74-83 Ponce Inlet FL
The footprint of the YSM 12 on the H30C is slightly wider than that of the 2GM20 that I repowered with. I don't know the dimensions of the Yanmar 2ym15, but from online pics,
you should be able to do that as well.
2YM15  2.jpg
MY installer simply put rails in the engine bay to narrow the mount area.
It has worked fine for the past 13 yrs.
The height of your proposed engine will not be a problem.

Save the installer some time and aggravation and you some money:
Remove the bulkhead on the port side of the engine bay and the "step" shelf above the bay.
You'll do a better job, and you'll learn a lot about the construction of your cabinetry.
If your installer says it's not helpful to him to do all that yourself,
ask how he's going to get the old one out and the new one in!
 
Last edited:
May 27, 2004
1,707
Hunter 30_74-83 Ponce Inlet FL
I repowered my H30C with a 2GM20. The footprint and height of the
Yanmar 2ym15 seems to be very similar based on the pics:
2YM15  2.jpg
But the YSM mounts are wider by a couple of inches.
I installed 'rails' to the inside of the engine bay to handle the difference.
It has worked fine for 13 yrs. The height is not an issue.
Check the clearance of the oil pan with the depth of the bay as well
to ensure shaft alignment room.
I removed the port side bulkhead and the "step platform" (not just the hinged step)
above the bay for installation.
The rest is planning and physics and muscle and more planning.
 
Oct 28, 2018
27
Hunter 30 Cherubini Kemah, TX
Swapped out the old YSB12 with a new 3YM20 12 years ago. Pricey, but in my mind I was planning on keeping her for quite some time so I bit the bullet on that one and never regretted it. The footprint is a bit different. The mounting blocks (?) needed to be built in a bit as the new engine is a little narrower then the YSB.
Glad to hear you were happy with the decision! Been Hearing and reading a lot of comments arguing against the expensive re-power.
 
Oct 28, 2018
27
Hunter 30 Cherubini Kemah, TX
There are a couple articles of engine mods on your boat here at SBO. One sailor rebuilt his original. The other I can't tell. Since you want to keep her, and it's not my money, I recommend the upgrade. I have the smoother 18HP in my 30T.

Practical Sailor talks about the engine in their review of the Hunter 30. They say your engine is adequate, but as the Toolman says "it needs more power!". I hope you document the swap for other older H30 owners.
Always liked The tool man Taylor. More power sounds great, I just hope I do more of an AL install than a Tim Taylor install

Thank you for the links to the articles and for the advice.
 
Oct 28, 2018
27
Hunter 30 Cherubini Kemah, TX
The footprint of the YSM 12 on the H30C is slightly wider than that of the 2GM20 that I repowered with. I don't know the dimensions of the Yanmar 2ym15, but from online pics,
you should be able to do that as well.
View attachment 186869
MY installer simply put rails in the engine bay to narrow the mount area.
It has worked fine for the past 13 yrs.
The height of your proposed engine will not be a problem.

Save the installer some time and aggravation and you some money:
Remove the bulkhead on the port side of the engine bay and the "step" shelf above the bay.
You'll do a better job, and you'll learn a lot about the construction of your cabinetry.
If your installer says it's not helpful to him to do all that yourself,
ask how he's going to get the old one out and the new one in!
Will definitely look into the rails. Anything that will keep costs down will help. Step and bulkhead you’re outta here!
 
May 12, 2004
1,354
Hunter Cherubini 30 New Port Richey
Glad to hear you were happy with the decision! Been Hearing and reading a lot of comments arguing against the expensive re-power.
Thanks. At that point I had already had Fraulein over 11 years and had done several upgrades on her. I know her inside and out and really enjoy sailing her. Knowing that I wouldn't get much for her without a functioning motor and then buying another vessel that I was going to have to possibly re-hab, it made sense to me to just do this upgrade. Yea, it was like buying her all over again, but at least I know what I have and am reasonably certain I won't get stuck out there when I really need that engine to fire up.
 
Nov 6, 2006
9,246
Hunter 34 Mandeville Louisiana
Don't know if you talked to the folks at Beta about the repower.. they can sometimes have the proper mounting spacers installed on their offerings to make it kind of a "drop in" .
 
  • Like
Likes: Woodrowbr
May 27, 2004
1,707
Hunter 30_74-83 Ponce Inlet FL
On a follow up note... Be aware,
some Yanmar engines have different size engine mounts front and back.
Make sure you get the correct ones.
 
  • Like
Likes: Woodrowbr
Jun 4, 2004
812
Hunter 340 Forked River, NJ
The original owner of my 1980 H30 was a Hunter dealer and he upgraded and installed a 2QM15 in the boat when he purchased it new for himself. Years later I had the engine and shaft re-aligned and the mechanic had to add rails to the engine compartment to get the engine in the right position. It seem OK up to that point but the eventually shaft wore away part of the stern tube thus the re-alignment.
 
Oct 28, 2018
27
Hunter 30 Cherubini Kemah, TX
Will definitely need to consider this.

Don't know if you talked to the folks at Beta about the repower.. they can sometimes have the proper mounting spacers installed on their offerings to make it kind of a "drop in" .
 
Oct 28, 2018
27
Hunter 30 Cherubini Kemah, TX
The original owner of my 1980 H30 was a Hunter dealer and he upgraded and installed a 2QM15 in the boat when he purchased it new for himself. Years later I had the engine and shaft re-aligned and the mechanic had to add rails to the engine compartment to get the engine in the right position. It seem OK up to that point but the eventually shaft wore away part of the stern tube thus the re-alignment.
Would you happen to have pictures of the rails?
 
Jun 4, 2004
812
Hunter 340 Forked River, NJ
It was a long time ago and I don't have a photo of the engine compartment. As I remember, the rails were strips of wood bolted to the inside surfaces of the original engine compartment stringers. That gave more surface area and allowed the engine mounts to be better placed. Looking over some of my notes from that era, I'm not sure that the boat yard and mechanic were of the highest quality and experince and they gave some questionable advice. Some of the things that were done to my engine had to be re-done by another an more experienced mechanic. I would suggest a second opinion and/or a survey of the area in question. Good Luck!
 
Oct 28, 2018
27
Hunter 30 Cherubini Kemah, TX
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.
 
May 27, 2004
1,707
Hunter 30_74-83 Ponce Inlet FL
I can get you pics of my set-up this week, which is similar to John T's description.
As to the lag screws for the engine mounts, drill out the holes (with the "rails" in place) slightly oversize and fill with thickened epoxy.
Do the same for the holes drilled for the vertical portion of the rail.
( You'll see them in the pics to follow)
Let cure and then drill normal pilot holes for the screws.
They will last longer that you and your children.

Thickened epoxy in a tube with video instructions here:

Or, mix your own for a thicker batch.
 
Last edited:
Oct 28, 2018
27
Hunter 30 Cherubini Kemah, TX
It was a long time ago and I don't have a photo of the engine compartment. As I remember, the rails were strips of wood bolted to the inside surfaces of the original engine compartment stringers. That gave more surface area and allowed the engine mounts to be better placed. Looking over some of my notes from that era, I'm not sure that the boat yard and mechanic were of the highest quality and experince and they gave some questionable advice. Some of the things that were done to my engine had to be re-done by another an more experienced mechanic. I would suggest a second opinion and/or a survey of the area in question. Good Luck!
Thanks will definitely get all the opinions I can.
 
Oct 28, 2018
27
Hunter 30 Cherubini Kemah, TX
I can get you pics of my set-up this week, which is similar to John T's description.
As to the lag screws for the engine mounts, drill out the holes (with the "rails" in place) slightly oversize and fill with thickened epoxy.
Do the same for the holes drilled for the vertical portion of the rail.
( You'll see them in the pics to follow)
Let cure and then drill normal pilot holes for the screws.
They will last longer that you and your children.

Thickened epoxy in a tube with video instructions here:

Or, mix your own for a thicker batch.
thanks for the help!