Looking to put 25" outboard on 20" transom...ok???

[CaptainHook]

Just a quick question, I am going to rig a 17' manatee bowrider for a buddy of mine. It currently has a johnson 110 on it but it has about seen it's day. I came across a really really nice, very low hour mercury 135hp that was for sale for an unbelievable price. (Was left to a guy by father in law). Compression is perfect, runs excellent. Everything works right.

The mercury is a 25" long shaft. The Johnson is a 20". Now, the guy gave me a jack plate with the motor as well. Will the jack plate make up the difference and be ok on this boat or will this just not work. BTW the transom is very solid.

 

[Silvertip]

Re: Looking to put 25" outboard on 20" transom...ok???

Use the jackplate and adjust engine mounting so the AV plate is at least flush with the bottom of the boat as a starting point. It will likely perform better and inch or so higher. Not using the plate will result in the lower unit so low in the water handling problems could result in high speed turns due to the long lever effect. It also means the prop is 5 inches closer to any under water obstructions. Not a good situation.

 

[CaptainHook]

Re: Looking to put 25" outboard on 20" transom...ok???

I wasn't going to mount it without the jack plate. i was just wondering if this would do the trick. And then, if I have the option, do you think bringing it up a bit more would help or make it ride like poo

 

[Dhadley]

Re: Looking to put 25" outboard on 20" transom...ok???

In this scenario as long as the AV plate (and therefore the prop and propshaft) are positioned correctly (according to the technology built into the prop and the hull) the motor length has little to do with anything. The jackplate is your key. I think you're on the right track. Keep us "posted" with your progress.