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Outboard swap

L

laterider

New member
Recently bought a Lowe aluminum 16' fishing boat with a 60 HP Yamaha outboard. I think this is too much motor both in power and weight for the boat. Bow rides too high and stern too low even when sitting still in water. I also have a pontoon boat with a 40 HP Mercury and I am thinking of swapping them. Question is: How much changeover problem will I have. The throttle and shift cables are larger diameter on the Mercury and they will have to extend further into the motor than the Yamaha. Are there interfacing parts I can purchase to use with the Yamaha and vice versa? The electrics, I think I can work out but I don't really want to purchase new cables for both. Any advice? What other problems am I overlooking? Thanks.
 
I reckon before you go spending money and exhausting effort by swapping engines, you should try different ways to distribute weight in the boat of your current setup. Despite the difference of manufacturer and hp between the 40 & 60, I can't imagine the difference in weight between the 2 motors is going to solve the issue (30-60lb?).

Skiffs like yours are notorious for performing exactly as you've described...especially if the motor is not equipped with power T/T to control bow angle. I'd shift as much weight forward as you can, then re-trial. I'd also verify the motor's AV plate is inline with the bottom of the hull, or at most 1" above or below. And you should be water testing when the engine is completely tilted down. If bow is still porpoising after shifting weight, drop engine height down on the transom (if it's not already). Also, installing a hydrofoil may help keep the bow down.
 
ClassicAQ, thanks for your help. Exactly the information I needed to stop me from making the mistake. I checked to find place in the front for the two batteries now located just in front of the motor. I will have to construct boxes to mount in the fishing platform but I think I can move them. The AV plate is within 1/2 inch from the bottom of the boat. Before doing anything, I will take it out again to try adjusting trim. It has hyd. trim adjustment but the first time I was having some running issues that have now been corrected. I hope I can find some prefabricated aluminum or plastic battery boxes that will mount flush with the floor with a hinged cover. If not I will try to make some. I think this weight distribution will probably be a good thing to do whatever I find on the next try. Thanks again for your help, I do appreciate it.
 
No prob. Prior to owning my current bigger boat I had 2 smaller skiffs, a 13ft & 15ft, both v-hull aluminum. Both of those hulls gave me same issues you're dealing with, so I'm familiar with the headache. Though the engine I had on both skiffs did not have power T/T, so dialing in the optimum weight distribution and engine height settings was a major pain. Since you can control bow angle while underway with your engines power T/T, I reckon when you've distributed enough weight forward you'll be running much better. Good luck.
 
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