I want to start off by saying that I am not interested in breaking the law with this, so don't accuse and/or tell me it's okay because no one checks, either way.
I would really like to see if anyone knows the rules as far as de-rating an outboard motor so that it can be installed on a certain boat without running over the horsepower limit set for the boat by the manufacturer.
Here is what I mean:
I have a 1996 FourWinns 170 Horizon with a maximum rated horsepower of 140. I have a friend who has a 150 horse V-6 that he wants to sell, so it is 10 horsepower over the boat's rating. When I was on the Kenai river, when it still had the 35 horsepower restriction on it, guys were buying 50 horse motors and having a service shop de-rate them to 35 horse instead of just buying a 35 horse motor, and I was told that this was because the 50 horse motor made more torque and had a broader peak torque range than the 35, so even at the same horsepower, the 50 de-rated made better, more usable power than the 35.
My situation is obvious, because the cutoff from 140 to 150 horsepower is the difference between a V-4 with a lower final drive ratio and a V-6 with better torque band, a higher final drive ratio, and just generally higher performance all around. A 140 horse V-4 and a 140 horse V-6 are not even similar in final performance - the V-6 will win in low end, top end and cruising.
My question, then, is is it legal to de-rate a 150 horse motor to 140 horse and mount it to my boat? I suspect that it is, because the restriction deals with final horsepower, and I didn't see where it discusses <i>manufactured</i> horsepower anywhere... Thoughts?
I would really like to see if anyone knows the rules as far as de-rating an outboard motor so that it can be installed on a certain boat without running over the horsepower limit set for the boat by the manufacturer.
Here is what I mean:
I have a 1996 FourWinns 170 Horizon with a maximum rated horsepower of 140. I have a friend who has a 150 horse V-6 that he wants to sell, so it is 10 horsepower over the boat's rating. When I was on the Kenai river, when it still had the 35 horsepower restriction on it, guys were buying 50 horse motors and having a service shop de-rate them to 35 horse instead of just buying a 35 horse motor, and I was told that this was because the 50 horse motor made more torque and had a broader peak torque range than the 35, so even at the same horsepower, the 50 de-rated made better, more usable power than the 35.
My situation is obvious, because the cutoff from 140 to 150 horsepower is the difference between a V-4 with a lower final drive ratio and a V-6 with better torque band, a higher final drive ratio, and just generally higher performance all around. A 140 horse V-4 and a 140 horse V-6 are not even similar in final performance - the V-6 will win in low end, top end and cruising.
My question, then, is is it legal to de-rate a 150 horse motor to 140 horse and mount it to my boat? I suspect that it is, because the restriction deals with final horsepower, and I didn't see where it discusses <i>manufactured</i> horsepower anywhere... Thoughts?
