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Originally Posted by
Ally410
I’ve only got experience with the Yamaha 30hp which have a similar model split I.e. a 2 cyl and a 3 cyl version. The 3 cyl Yamaha, whilst heavier, is quite a bit smoother to operate, particularly at low revs, it also has a larger displacement than the 2 cyl (as the Mercury’s you’ve quoted do) which generally translates in my opinion to the larger displacement engine having to work less hard to produce the same horsepower, which theoretically translates to potentially a longer life. That said, I had the yam 30 2 cyl for 17 years and it never missed a beat, I also appreciated the less weight the 2 cyl had than the 3 cyl equivalent on my AllyCraft 410. That said, I didn’t do a lot of low speed running, when I did the 2 cyl would tend to oil up a bit, nothing major but noticeable when you hit the throttle to get up on the plane again after a period of idling.
In short, depends on your use. I think the 3 cyl would probably be the better long term, all round proposition if you weren’t worried about weight.
All of the above of course assumes similarity of principles between the yam and the Mercs which I think would be a reasonable assumption.