level in water for a 3HP

R

rickinri

Cadet
Joined
Oct 22, 2005
Messages
19
I have a 3 HP Evinrude folder, I am modifing a custom Herreshoff out board bracket for a 1917 Herreshoff sail boat, that allowed You to attach and outboard to the transom, it was made for a long shaft OB so I am lowering the mount to get the 3 HP lower in the water. Just how far down should the shaft of the moter go into the water, with out the modification is just barely covers the prop when on the boat. In relation to the anti cavitaton plate and the coupler that lets You fold the shaft , between those 2 points were should the water level be ?
Thanks
 
P

Paul Moir

Admiral
Joined
Nov 5, 2002
Messages
6,847
Re: level in water for a 3HP

Theoretically you should take it down 5" to make the difference between the longshaft and short, but really the deeper you can get the engine in the water the better on a sailboat. You absolutely must have it so the water pump, which resides at the bolted seam between the lower unit and the breaking midsection, is underwater when the engine is started, But since a sailboat rolls, the propeller has a tendency to come out of the water. Hence the deeper the better.

This was brought home to me late one night, as I had to motor through heavy swells at about 3 knots for 6 hours to prevent the motor from overrevving.
 
R

rickinri

Cadet
Joined
Oct 22, 2005
Messages
19
Re: level in water for a 3HP

So if it went as deep as the joint were the shaft fold ,should be no problem?
 
P

Paul Moir

Admiral
Joined
Nov 5, 2002
Messages
6,847
Re: level in water for a 3HP

No, no problem at all. You want to have the exhaust idle relief ports above the normal water line if you can so back-pressure is properly relieved.
 
You must log in or register to reply here.
Top