Repowering my H30

[dbecker68]

I'm forced to replace the Yanmar 2GM engine in my 1982 H30, DreamBoat. Threw a rod, cracked the case, not repairable at any price, it's a long scary story, but that's not why I'm posting.
My choices are a 2YM 15 @ 14 horsepower, or a 3YM20 @ 21 horsepower. My mechanic says that either one will fit without major problems. The cost difference is negligible, the weight difference is less than 40 pounds, but obviously the horsepower is a big difference.
I have always considered that the boat was underpowered, but does anyone have experience or knowledge about either of these engines? What are the pluses and minuses of a more powerful engine?
I'm an accountant, not a mechanic. I trust the mechanic, but I'm just looking for a second opinion. Any input would be welcomed. Thanks in advance.

 

[Paul F]

My 2QM15 (14hp) also bit the dust last year. Replaced it with a 3YM20. Could not be happier. Can reach hull speed now without effort. Highly recommend the 3YM20. The 3YM20 is wider than the 2QM15 but it fits fairly well in the same engine compartment.

 

[Ed Schenck]

There are two 3YM installations in "Hunter Owners Mods" under the 37-cutter. There you can see how we dealt with the mounting issue. The 3YM mounts are narrower than the 2QM. Not sure about the 2GM. Also don't know how Paul handled the mounts.

 

[kloudie1]

Having had a little experience with both those engines, I think you'll find the 3YM to be smoother and quieter. It will use about the same amount of fuel since it is a little more efficient..I would go with the 3 .. you'll probably have to buy a new prop to match the higher horsepower. Sounds like an interesting story ??

 

[malyea]

Just planning ahead for repowering.....what do you expect the total cost to be...ballpark?

 

[Ed Schenck]

Call a dealer and get a price. If you can do all the work yourself as I did then add marina costs. I had them lift the old out and the new one in at no cost because I bought the Yanmar from them. My 3YM30 was $7000. but in 2004. That doesn't count a prop and shaft which I also installed. A friend found his motor seized up when he went south to bring his boat home. He had a new Beta installed for around $10,000.

 

[dbecker68]

Update on repowering my H30

This has been a comedy of errors. My local mechanic (in Mobile, AL) recommended going with the 2YM15, said it would fit better, would be quicker to install, etc. So we are going in that direction, but Murphy's Law has been at work.
The new engine is slightly narrower than the old, so the motor mounts have to be "adjusted". The exhaust is on the opposite side of the engine, so that needs to be "modified". The latest development is that the mechanic "made a mistake" and bent the prop shaft:cussing:. The good news is that he is taking the responsibility (and the cost) of replacing the shaft. The bad news is that it will be another week or two until DreamBoat is ready to come home.
The total cost is projected to be under 10K, but just barely.:cry:

 

[MLampner]

My YSB 12 reached the end of the linearly this summer. Not know what your power plant was you may or may not run into some of these issues.

First the 15 needed a bigger raw water intake then the exhaust was the wrong size and place. The 12 was one of the few leftys so I needed a new prop.

Ended up running me just over the 10 mark but love the new engine, it was a great sailing boat before but if the wind dropped it could be a very long way home. The power plant really expanded my range and made me much more comfortable single handing the boat. I know I can rely on it get me out of trouble which I really couldn't with the old engine.

The only think I miss is the magic fingers feeling the old one banger had. It was just like being a kid in a motel in the 50s. lol.

 

[dbecker68]

First the 15 needed a bigger raw water intake then the exhaust was the wrong size and place. The 12 was one of the few leftys so I needed a new prop.

Thanks for the info MLampner. Yes, my exhaust is in the wrong place, compared to the old one. I have not heard about the raw water intake, or the lefty vs. righty, but that could have had something to do with bending the shaft?
I do hope the new engine (with 3 more HP) will be more powerful than the old one. LIke you, I sometimes wondered if the old engine was a little too undersized to get me out of trouble (read: big waves, bad tides and currents).
I hate it that I missed some of the best fall sailing weather. October and November are really great on the Gulf Coast, not too hot, not too cold. Ther's always next spring, and with luck, there will be a few warmer winter days, too.

 

[MLampner]

Even if the nominal power rating wasn't 3 more given the age of the original engines I doubt they were capable of reaching th 12 hp at full throttle and everything adjusted as close to tolerance as possible unless they had been completely torn down and rebuilt. So the gain is more than simply 3 hp. I also theorize that my old transmission lost some of the limited power to slip through the cones that made up its "clutch". If like me you need a new prop it too may contribute to better transfer of power to thrust.

All in all I know on a calm day running against a similar current I am able to move far faster. The current in Middle River when a normal tide heads out is about 2 knots fighting it with the old engine on a calm day might move me at 3.5 to 4 knots. I know can routinely do close to 6 with out getting anywhere near full throttle.

Good luck, I think you'll be very happy when it's all done. Like you I lost some prime season this year but the sailing after it was done was great and knowing we could get back if the weather changed made it a much longer season. Us poor northerners usually pull early Nov but this year she will be afloat till next week.

 

[dentonflyer]

My 1979 Hunter 30 had a 3HM installed. Great power and good engine. I would go with the 3 cyclinder. My sea water intake is under the sink on the starboard side so no problem running the hose to the waterpump on the front of the engine.