motor height on old johnson

[jdsgrog]

I've been reading on these forums about motor height, and I had a question on the old Johnson and Evinrudes. I have a 15 inch transom on my boat, but the cavitation plates on my '56 10hp and '58 hp are a couple of inches below the bottom of the boat. Would raising the motor to get me better performance or is there a reason the old OMC motors were designed this way?

 

[coolguy147]

Re: motor height on old johnson

put it low as possbile on that transom cause the water pump intake is higher then the newer motors

 

[jdsgrog]

Re: motor height on old johnson

thanks. i thought there was a reason for the lower height. i thought i read that it wasn't recommended on one of the threads, but i couldn't find it.

Another question, i was thinking on putting a hydrofoil on my motor(s), but because the cavitation plate is so low, would it be worth putting the hydrofoil on? would it adversley affect the performance?

I was thinking putting smart tabs on, but the problem is that I would be switching motors between these as well as a third motor (33hp) depending on the lake and number of people in the boat, so if I went smart tabs, I would need to get a different actuator for the different motors.

 

[coolguy147]

Re: motor height on old johnson

i believe smart tabs would be better for the long run. one thing i can say is that when my john boat is on plane the water i pararell to the part where the lower unit is attached to the motor like where the bolts r. so the dolhpin will still be under water and would cause drag which lose in top speed and inneccary stress on engine

 

[jdsgrog]

Re: motor height on old johnson

hmmm...i guess i'll have to think of what to do. I'll contact nauticus and pick their mind.