Mounting an outboard..

[stevo2256]

I am mounting a re-buildt 90HP Evinrude on my fishing boat of 18 years. The previous motor (a Mariner 60HP) doesn't have enough go for the kids to ski(me too!) My question is...What is the correct height for mounting. I want to make sure that the cavitation plate and prop are properly placed for best performance. Does anyone know of a "down and dirty" process for this, or do I need to get some manuals to follow?

 

[VistaMan]

Re: Mounting an outboard..

What is the shape of the hull? Usually with a "v" bottom the motor would be mounted wuth the prop shaft about 2-3 " below the bottom of the V.

 

[Dhadley]

Re: Mounting an outboard..

Your correct X dimension will depend on your intended use, set up (Jackplate or not -- set back or not or how much) and what prop you are going to use. All this has to work with your hull design (V, deep V, flat, pad bottom, pad bottom with a step, tunnel etc.). Balance comes into play also.<br /><br />Tell us more about your rig, especially the intended prop brand and style.<br /><br />Good luck!

 

[stevo2256]

Re: Mounting an outboard..

Thanks guys for the response. My boat is a 16' Lund Renegade. It has a deeper "V" hull and has served me well for many years. Currently, the set-up would push my prop 6-8" below the bottom of the hull. I will attempt to utilize the different mounting holes to achieve a 2-3" range if indeed that is correct. Please advise before I drill any holes into the transom. Thanks!

 

[Dhadley]

Re: Mounting an outboard..

No more holes are required. <br /><br />What prop are you going to use?

 

[quantumleap]

Re: Mounting an outboard..

The general rule of thumb is to mount with the cavitation plate even with the bottom of your hull, then you can fine tune from there.

 

[stevo2256]

Re: Mounting an outboard..

Prop: Standard Alum., cupped 17 or 19 pitch.

 

[Dhadley]

Re: Mounting an outboard..

OK. We assume from your answer that you will not be using a jackplate or a setback. Depending on what brand prop you use you can safely mount the motor so the AV plate (the plate right above the prop) is even or slightly above the hull right in front of the prop. <br /><br />Once you get it going you can try the motor up a little and adjust it from there for your intended use.

 

[stevo2256]

Re: Mounting an outboard..

Thanks for the help gentlemen! Remember...a bad day fishing beats a great day in the office!