Engine Height/Depth

P

phipps

Petty Officer 1st Class
Joined
Jul 20, 2008
Messages
385
We just repowered our 1977 24' Sylvan pontoon. In the process I rebuilt the transom.

The old motor was a 28hp and they had the transom raised up one hole from being fully seated. My new motor is a 50hp and I fully seated the transom.

I'm wondering if my motor is too deep in the water. I get tons of splash coming off the new motor. I have attached a couple photos of how it sits when not running. I think it looks too deep.

Thoughts, suggestions and ideas would be greatly appreciated!



Thanks,

Gary


1.JPG

2.JPG
 
G

Georgesalmon

Lieutenant Commander
Joined
Apr 14, 2012
Messages
1,793
Re: Engine Height/Depth

Every boat/motor combo runs a little differently. Best thing for you to do is raise the motor one hole and try it out. Looking at pictures won't mean much unless its really bad. Like a 25" leg on a 20" transom.
 
P

phipps

Petty Officer 1st Class
Joined
Jul 20, 2008
Messages
385
Re: Engine Height/Depth

When I'm out on the lake running, what should I be looking for? ie how deep should the leg be in the water? Should the cavitation plate be visible/not visible?
 
L

lakegeorge

Senior Chief Petty Officer
Joined
Mar 19, 2002
Messages
660
Re: Engine Height/Depth

phipps said:
We just repowered our 1977 24' Sylvan pontoon. In the process I rebuilt the transom.

The old motor was a 28hp and they had the transom raised up one hole from being fully seated. My new motor is a 50hp and I fully seated the transom.

I'm wondering if my motor is too deep in the water. I get tons of splash coming off the new motor. I have attached a couple photos of how it sits when not running. I think it looks too deep.

Thoughts, suggestions and ideas would be greatly appreciated!



Thanks,

Gary


View attachment 209477

View attachment 209478
Click to expand...

Gary, The cavitation plate on your motor should be even or 1/2" below the bottom of your boat. Yours looks way to low.
 
P

phipps

Petty Officer 1st Class
Joined
Jul 20, 2008
Messages
385
Re: Engine Height/Depth

lakegeorge said:
Gary, The cavitation plate on your motor should be even or 1/2" below the bottom of your boat. Yours looks way to low.
Click to expand...

Since it's a pontoon, when you say bottom of boat, do you mean bottom of the pontoons or transom?
 
MH Hawker

MH Hawker

Vice Admiral
Joined
Jul 13, 2011
Messages
5,516
Re: Engine Height/Depth

The motor height is set to how it is while running at WOT, not how it looks while its sitting. It should be set so the cav plate is just under the surface while running, how ever due to all of the turbulence deeper is better. The best way I have found is to start deep and raise it a hole at a time till it starts to lose the bit or blows out then drop it back down.
 
P

phipps

Petty Officer 1st Class
Joined
Jul 20, 2008
Messages
385
Re: Engine Height/Depth

MH Hawker said:
The motor height is set to how it is while running at WOT, not how it looks while its sitting. It should be set so the cav plate is just under the surface while running, how ever due to all of the turbulence deeper is better. The best way I have found is to start deep and raise it a hole at a time till it starts to lose the bit or blows out then drop it back down.
Click to expand...

When you say raise it a hole, are you meaning the holes on the motor bracket?
 
G

Georgesalmon

Lieutenant Commander
Joined
Apr 14, 2012
Messages
1,793
Re: Engine Height/Depth

yeah, most motors have three holes so you can raise the motor an inch or so at a time for best performance.
 
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