Is a 2QM15 a worthy upgrade from a YSM12

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Sep 25, 2008
2,288
C30 Event Horizon Port Aransas
I pulled the head already. They look a little different headless, as any of us would. the plaque has 1273 on the lower right, maybe the date of manufacture?

I have a question for those who know. Does that water pump look like it's designed to have a raw water side and fresh water side?
 

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Nov 22, 2008
3,562
Endeavour 32 Portland, Maine
I guess maybe that is a 2QM20. I would have to look at the manual that I don't have here to be sure.

Did this engine come from a powerboat? That looks like a very heavy duty, large reduction gearbox. If you can turn the engine over, you should check the gear ratio. It's probably way too large a reduction for the size prop you can fit on a typical sailboat.
 
Nov 22, 2008
3,562
Endeavour 32 Portland, Maine
I believe the reduction ratio is 2.3:1
What ratio does your have?
That's about what mine is but that gear on your engine looks massive and with a lot more shaft drop than what is on my engine. You need to either find a nameplate or see how many turns of the coupling it takes to make the flywheel go around once. Now that the heads are off, that shouldn't be too difficult.

I should be able to look at my manual tomorrow.
 
Sep 25, 2008
2,288
C30 Event Horizon Port Aransas
I haven't looked all over for a name plate on the tranny. I got that number by marking the crank and output and turning it over once.
I am estimating the 2.3:1. But if it's not that it is very close. It was said to have come out of a sailboat.
That shaft drop will make this boy stand up tall in the engine compartment.
Do you think the water pump looks like one that is a pump for fresh and raw water? There are 4 ports on it.
 
Nov 22, 2008
3,562
Endeavour 32 Portland, Maine
Do you think the water pump looks like one that is a pump for fresh and raw water? There are 4 ports on it.
It looks to me more like the optional bilge pump option that they offered since there doesn't seem to be a heat exchanger. You need to contact Torrensen Marine and buy the manuals, you're only looking at about 30 bucks and they include complete instructions for disassembly and rebuilding. There is a service manual about an inch thick and a parts manual.

I've got a proposal to get out and my boat to get to a safe place before the weekend so I'll have to talk to you more next week. The manuals will answer more questions than you could ever have time for here.
 
Nov 26, 2006
381
Hunter 31 1987 Fly Creek Marina Fairhope,AL.
I am in the same boat, " no pun intended ". Have the YSM-12 in my hunter 30 and feel it its under powered for cruising in our waters. Hired a dependable mehanic to check it out and price new 2Ym-15 FRESH WATER cooled verses raw water.

Found out by the name plate on the YSM-12 that it is on 10 HP so the new 2YM-15 would be a 30 % increase in HP and worth it in my book for sure.

Cost of NEW yanmar 2YM-15 here is abt $6K for new engine/controls/panel/ and wiring harness. I am saving for it now verses taking out a small loan.

Good luck.
 
Nov 22, 2008
3,562
Endeavour 32 Portland, Maine
I the new 2YM-15 would be a 30 % increase in HP and worth it in my book for sure.
But, only if you can install a prop that can use the additional horsepower. Many sailboats have a prop that is already too small to efficiently use the horsepower installed (H.P. appears in the brochure and is easily understandable, prop characteristics are not.). Adding horsepower may not significantly improve performance.

Don't spend a lot of money on a horsepower upgrade without getting complete propeller calculations done.
 
Nov 6, 2006
10,219
Hunter 34 Mandeville Louisiana
After figuring the correct pitch, you can take the propeller to a good propeller shop and have them re-pitch the prop and balance it if necessary.. Much less expensive than a new prop.. If the prop was correctly pitched for the lower HP engine, with the same ratio transmission, the prop pitch will have to increase a little to make it right.. Re-pitching is limited so this may not be an option if the transmission ratio is very different..
 
Sep 25, 2008
2,288
C30 Event Horizon Port Aransas
To abide by the rule to have enough clearance between the prop tips and the hull, I am limited to a 12" prop.
I don't know if a 13" prop would be worth getting a half inch closer to the hull. 13" props are much easier to come by also.
The manuals I saw were $105 for the parts manual, the service manual, and the operator's manual. I will look for a deal, but that is one thing I just can't do with out.
 
Nov 22, 2008
3,562
Endeavour 32 Portland, Maine
I should be able to look at my manual tomorrow.
I was able to take a quick look today while moving the boat to her storm berth and, sure enough, one of the gear options is one that looks just like yours. It looks like a more substantial gear than the Hurth on my engine, the kind you would put in a powerboat instead of a sailboat, but the reduction ratios are not greatly different.
 
Nov 6, 2006
10,219
Hunter 34 Mandeville Louisiana
I think that optional gear was to better fit into a classic full keel boat.. with the prop in an aperture .. engine much more accessible than if used with a “normal” drop gear.. Interesting.
 
Sep 25, 2008
2,288
C30 Event Horizon Port Aransas
I just got back from the boat. I did some measurements and found I would need 5" or 6" longer compartment and about 3" to 4" taller. The stringers won't need any width changes. I can definitely accomodate for the extra space, but I will need to weigh this engine and see if it is in the rhelm of possiblity. If she can handle the weight, I will build a removable wooden housing.
I tore the engine most of the way down. It looks like someone rebuilt it recently. before I replace anything I am going to have some measurement on tolerances done by a pro I trust. I could have this in my boat for under $500 in parts.
just got the cabinet mounted and a through hull for the drain installed and working. I just got the pressure pump for the water working today. The water that came out tasted clean though I may die from some preserving chemical a PO put in there.

I can see why I haven't had a response with anyone saying they have the 2Qm20 in their C30. It will not fit the way the cabinet is now.
 
Dec 9, 2008
426
1980 Hunter 30 "Denali" Seaford, VA
I just got the pressure pump for the water working today. The water that came out tasted clean though I may die from some preserving chemical a PO put in there.
I think Peggies book goes over cleaning the water tank and system if you have it. I would consider a water filter if you will be drinking from that water. We use that water mainly for washing hands, showers, and doing the dishes and bottled water for drinking. I think I will put a filter on though for next season.
 
Sep 25, 2008
2,288
C30 Event Horizon Port Aransas
I'd have to have a water filter to drink from it also. Maine sail says he drinks out of his tanks but he filters it thoroughly. We always drink bottled water so we are used to the taste. If I could get it to taste like bottled water, we would drink it though.
 
Nov 22, 2008
3,562
Endeavour 32 Portland, Maine
Feb 26, 2004
23,353
Catalina 34 224 Maple Bay, BC, Canada
Drinking water

If I could get it to taste like bottled water, we would drink it though.
You never will if you don't try.

To obtain Peggie's tank cleaning sequence, do a search on the word "recommission" by author.
 
Jan 27, 2008
3,092
ODay 35 Beaufort, NC
Come on buy peggie's book

Peggy probably only gets a buck or two royalty from each sale. We all owe peggy a lot more than that for all the free advice she has given us. Fork up some cash and buy her book.
 
Feb 26, 2004
23,353
Catalina 34 224 Maple Bay, BC, Canada
jibes, FYI, Peggie has "republished" those instructions right here many times, and continues to do so. I also think it's a great idea to buy her book because there's so much more in the book than just the water post.
 
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