Motor/lower unit under transom how long

[Mike 1]

I have a evinrude 10 HP. I am going to use it on a 14 ft jon boat. The transom on boat is 16-17 inches from the top to the bottom of boat. The motor is from where it sets on top of the transom to the bottom of the skag, is 29 inches. From the same where to motor sets on the transom to the center of the prop is 22-23 inches. does this sound like it would be ok to use? Is there any certain measurements that I should go by? Thank You, Mike 1

 

[marine4003]

Re: Motor/lower unit under transom how long

Ideally, the cavitation plate../ plate directly above prop / should be in line with the bottom of the hull. any longer ,no big deal..a tad more drag...higher and you will experience prop slip, prop wont get a bite.

 

[Mike 1]

Re: Motor/lower unit under transom how long

Thank you. Mike 1

 

[tmcalavy]

Re: Motor/lower unit under transom how long

The plate above the prop can be up to 2 inches above the keel, depending on the motor and prop. Sounds like you will be in the ballpark anyway. What year is your Evinrude? Motors older than early 70's need to run deeper because of where the water intake...they should be even with or deeper than the keep of the boat.

 

[marine4003]

Re: Motor/lower unit under transom how long

The plate above the prop can be up to 2 inches above the keel, depending on the motor and prop. Sounds like you will be in the ballpark anyway. What year is your Evinrude? Motors older than early 70's need to run deeper because of where the water intake...they should be even with or deeper than the keep of the boat.

Again, depending on what type of hull...boston whalers for one dont run well that high, upon acceleration the prop slips,as with alot of "flat bottom" boats theres too much water being directed at the lower unit across a flat plane.

 

[tmcalavy]

Re: Motor/lower unit under transom how long

So...is it a jon boat or whaler? Either way, the best way is to test it without endangering the outboard...make sure the water intake is well submerged.