# 9.5hp to 18hp on a boat rated for 15hp



## samuelh1987 (Apr 15, 2018)

After getting my 9.5 sorted and still wanting more umph, I have someone wanting to swap for a 18 Evinrude Fastwin. Would I have a significant gain in performance on a wide bodied 12' sea nymph 12r V-hull? Also, is the integrity of the hull safe if a bit overpowered?


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## turbotodd (Apr 16, 2018)

....Lot of "duck hunters" out here are putting 70-90hp motors on 1542's, 1548's, and 1552/1556's.

I wouldn't sweat it unless the waterway police are anal about it in your area. Apparently they've gotten lax about it out here.


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## Pappy (Apr 16, 2018)

The 18hp Fastwin is a great engine. Feed it plenty of oil and it will reward you with years of good service. 
Not recommending overpowering by any means but each and every one of my boats is over powered except for Lesa's Lyman. 
Engines have throttles and it is up to you to run with common sense. I have never even been asked about how much horsepower I have on the back of any one of my boats even when I am over double the rated horsepower.


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## samuelh1987 (Apr 16, 2018)

Thanks for the feedback. I was worried about the weight more than anything else since this is a short boat, but, i'm sure the benefits of double the HP will overcome that. I've heard nothing but good things about the elder Fastwins, so, I'll probably give it a shot.


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## samuelh1987 (Apr 16, 2018)

Here is the motor, cosmetically it's worse off than my 9.5 but I have video of the motor running on the lake from yesterday evening. It's just a bit of a gamble still.


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## CedarRiverScooter (Apr 16, 2018)

The over-hp issue would be a concern if you caused an accident/injury & speed was a factor.

Like Pappy said, the driver controls the throttle.

You could also put a throttle stop on it, so if you let others drive the boat they don't get surprised when they open it up.


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## Weldorthemagnificent (Apr 16, 2018)

That 18 probably only weighs less than 20 lbs more than the 9.5. Stand in the back of your boat and hold something that weighs 20lbs. That’s what your boat will feel like with the 18. As for the power, either take a buddy fishing or put some weight up front. 


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## samuelh1987 (Apr 17, 2018)

Took out the new motor. All I can say is Wow. It flat out flies on my 12r. Starts easy, runs like a dream, but, is missing the choke knob. It popped up on plane as soon as I throttled up, I am super pleased. Now to repaint, get a carb kit, spare fuel pump, etc just to be safe.


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## Weldorthemagnificent (Apr 17, 2018)

Right on!


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## Pappy (Apr 17, 2018)

I would run that engine with a bit more oil than you may think you need. It's old and will benefit from it. If you give me the model # I will pinpoint the year for you.


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## samuelh1987 (Apr 18, 2018)

It's a 1967 I do believe. 18702R-E09590. It runs great at the moment. It may be old / ugly, but, is clean under the hood. Ordered a choke knob and detent last night, hopefully, I'll have them by the weekend.


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