I have a theory that the Hunter 31 is underpowered with the factory installed Yanmar 2GM20F. Granted it will do hull speed if the bottom is clean and you are not fighting a strong head wind. However, with less than Ideal conditions the engine will not do 6 kts. And tends to overheat above 3000 rpm. I believe the H31 is the largest boat they used the 2GM20 on. I know my neighbor’s H33 has the 2GM30. I am wondering if others are experiencing the same thing.
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nick maggio
326
they still use 2gm20 in 326 I have heard complaints from some not all, I have 290 same boat as 306 it has 2gm20 I have no problems with power except once the prop needed cleaning and everything has been fine since,
they still use 2gm20 in 326 I have heard complaints from some not all, I have 290 same boat as 306 it has 2gm20 I have no problems with power except once the prop needed cleaning and everything has been fine since,
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Ray
Underpowered
Replaced the 2gm with a 3gm in my 31. It made the greatest difference when motoring into strong headwinds and currents. Never a problem reaching hull speed. I sold the 2gm for about 1/2 the cost of the new 3gm.
Replaced the 2gm with a 3gm in my 31. It made the greatest difference when motoring into strong headwinds and currents. Never a problem reaching hull speed. I sold the 2gm for about 1/2 the cost of the new 3gm.
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David
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Jon
Auxilary power
I believe the original engine put in the 31 was a 2GMF and was 13hp. Yes, I think this is underpowered for the size of the boat. I now have a new 2GM20F in mine which is 18hp. This is a direct bolt in replacement and an adequate engine for the boat. Some will say you do not need the extra power in a sailboat. Also, if my original engine was salvagable I probably would have kept it. However, I take my children out with me and when you are bucking a current and the wind through an inlet the insurance the extra horsepower provides is a better value than my homeowners or life insurance premium in my opinion. You hope you won't need it, but it's important to have. -Jon
I believe the original engine put in the 31 was a 2GMF and was 13hp. Yes, I think this is underpowered for the size of the boat. I now have a new 2GM20F in mine which is 18hp. This is a direct bolt in replacement and an adequate engine for the boat. Some will say you do not need the extra power in a sailboat. Also, if my original engine was salvagable I probably would have kept it. However, I take my children out with me and when you are bucking a current and the wind through an inlet the insurance the extra horsepower provides is a better value than my homeowners or life insurance premium in my opinion. You hope you won't need it, but it's important to have. -Jon
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Ken Palmer
H33 has 2GM installed
If I recall, my 1981 H33 has simply a Yanmar 2GM. This was rated at 15hp. Yes, it is a bit underpowered. The archives state that replacing the prop with a 3-blade makes a big difference. Ken Palmer, S/V Liberty
If I recall, my 1981 H33 has simply a Yanmar 2GM. This was rated at 15hp. Yes, it is a bit underpowered. The archives state that replacing the prop with a 3-blade makes a big difference. Ken Palmer, S/V Liberty
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John Blakely
concur - underpowered
I have a l985 H31 with the 2GMF 13. I think it is underpowered when wind, current, and/or waves are strong. Other times its, ideal. Low fuel use, dependable, with a fairly clean bottom, up to hull speed. I am planning a trip from Baltimore to Cape Cod and back next year and am concerned about getting into the above conditions on the way up when I need some umpf! I was intreagued by the gentlman who sold his engine for half the price of a new one. Anyone want to buy my engine, 1200 hours; thats about the only real gripe I have with the boat and only in heavy weather. I think in heavy weather with a heavily reefed sail plan, its Ok, but I also would like the insurance of some more push.
I have a l985 H31 with the 2GMF 13. I think it is underpowered when wind, current, and/or waves are strong. Other times its, ideal. Low fuel use, dependable, with a fairly clean bottom, up to hull speed. I am planning a trip from Baltimore to Cape Cod and back next year and am concerned about getting into the above conditions on the way up when I need some umpf! I was intreagued by the gentlman who sold his engine for half the price of a new one. Anyone want to buy my engine, 1200 hours; thats about the only real gripe I have with the boat and only in heavy weather. I think in heavy weather with a heavily reefed sail plan, its Ok, but I also would like the insurance of some more push.
ours is the 2GM20F
Ed: You need a different prop. I have a 1985 H'31 witht he 2GM20F engine. If you have the original prop you are probably OVER propped. I would suggest that you look into having your prop repitched or getting a three blade prop that is correct for your engine/transmission ratio. I had the same problem on mine and switch to one of the CDI composite props. It is better but still a little too much pitch. I think that a 15 x 9 or 10 2 blade would be best. I am planning on have Bay Props repitch my original 2 blade and put on the winglets and cup it. They charge $135 for the service but it is worth trying.
Ed: You need a different prop. I have a 1985 H'31 witht he 2GM20F engine. If you have the original prop you are probably OVER propped. I would suggest that you look into having your prop repitched or getting a three blade prop that is correct for your engine/transmission ratio. I had the same problem on mine and switch to one of the CDI composite props. It is better but still a little too much pitch. I think that a 15 x 9 or 10 2 blade would be best. I am planning on have Bay Props repitch my original 2 blade and put on the winglets and cup it. They charge $135 for the service but it is worth trying.
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Steve O.
clarification
I believe the 33.5 is the largest Hunter model with the 2 cylinder 18 hp 2GM20 installed. I have a 1988 with 2GM20F and it is underpowered in certain situations (headwinds and chop) Also, there is no such model as a 2GM30, I think you mean 3GM30 (3 cylinders, 27 hp)
I believe the 33.5 is the largest Hunter model with the 2 cylinder 18 hp 2GM20 installed. I have a 1988 with 2GM20F and it is underpowered in certain situations (headwinds and chop) Also, there is no such model as a 2GM30, I think you mean 3GM30 (3 cylinders, 27 hp)
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Brian
what is you max rpm?
When you engine is warmed up, run it wide open with it in gear to find your max RPM. You want to run 200-400 RPM's lower than the max. 3000 may be in your range, but it seems high to me. I have the older 2QM15 from yanmar and run 2300-2400 typically. You have a bigger, nicer motor than me so you may be able to run that high, but just wanted to mention it since your running hot. As for it being underpowered I really can't say, but I get 6 miles (statute) an hour on an H30 in slack water.
When you engine is warmed up, run it wide open with it in gear to find your max RPM. You want to run 200-400 RPM's lower than the max. 3000 may be in your range, but it seems high to me. I have the older 2QM15 from yanmar and run 2300-2400 typically. You have a bigger, nicer motor than me so you may be able to run that high, but just wanted to mention it since your running hot. As for it being underpowered I really can't say, but I get 6 miles (statute) an hour on an H30 in slack water.
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