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Posts: 3
| I am still enjoying my Dads original 1985 Lund Nisswa side console. Still has the original 50 HP Mariner on it which has seen better days and is a little under powered.
I was thinking replacing the motor with a tiller this year but it looks like it is only rated for 50 hp.
Does anyone have experience with a Nisswa from back then with 50hp tiller? How well did it push the boat?
I am worried on the performance with 3 people in the boat since the 50hp I have now seems to struggle. It may just be the age of the motor though.
The side console is rated for a 80hp. Would I be better off just looking for a 75hp remote steer?
Also how does anyone know how the weight of the newer motors affects the ratings on older boats?
Thanks
Edited by jrucks 3/7/2018 5:29 PM
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 nisswa.jpg (186KB - 610 downloads)
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| Not sure what the answer is but I know my older 18' Pro V tiller is rated at 90hp but with a side console it was rated at 150. Same hull. I don't know all the reasoning but normally the tiller rating is considerably lower than console. |
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Posts: 3480
Location: Elk River, Minnesota | Hiya,
I would say go for the highest HP you can get and stay with the remote steer. One major advantage I think you will see is that somewhere in the late 80s? I believe they changed the HP ratings on the motors to be at the prop rather than at the main shaft of the engine.
If my memory serves me correctly, the current mariner on there would be acting more like a 35 to 40hp motor at the prop, whereas on a newer generation motor that is 50hp, it would be 50 hp at the prop... A nice gain...
So...if you go with a 70 or 75, you'd have a boat that would move along nicely.
the only thing I would be concerned with is going to a 4 stroke motor, though...with that vintage of boat, they were never designed for the weight of a 4 stroke as compared to the 2 stroke. It is not in that the transom couldn't handle it...but level floatation. I could easily see if a 4 stoke was put on, the boat would squat quite a bit.
I'd say, if you can find it, go with a 70hp Yamaha. It is the same displacement as their 90hp model, but with a little more in it than 70 hp. Also if memory serves me correctly, motor manufacturers are able to list a motor's HP at a certain value so long as it is within 10% of what it dyno'd at. So...when you see motors that have the same displacement but different HP, they are playing with fuel/air settings with carbs motor, and possibly exhaust tuners as well and different head tightness/compression...at least that was the case with yamaha.
So...the yamaha 70hp most likely was running more around the lines of 76hp, while the 90 hp was most likely running like an 82hp or so....close enough to call them 70 and 90 with jetting, exhaust tuning and head compression...
Steve
Edited by VMS 3/7/2018 8:18 PM
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Posts: 32885
Location: Rhinelander, Wisconsin | North of 8 - 3/7/2018 6:23 PM
Not sure what the answer is but I know my older 18' Pro V tiller is rated at 90hp but with a side console it was rated at 150. Same hull. I don't know all the reasoning but normally the tiller rating is considerably lower than console.
USCG rates the HP through a formula which takes into account how quickly a boat can be turned at WOT with either wheel or tiller, where the driver and passengers are situated in the boat for forward vision, etc. |
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| That makes sense Steve. I know my Pro V when I first bought it was a bit of a learning curve. With a 90hp you need to use some caution when turning with anything over half throttle, would really be scary with a 150 tiller, in fact I don't think it would be safe. |
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