1997 Tracker/Mercury 20 hp

[MrGrumman]

So I measured my "shaft length" on this motor and it is 22". I thought standard lengths were 15",20" and 25". Am I missing something ?

 

[FuzzyGrub]

Common to be an inch or two longer than transom height. Many outboards recommended install height is 1” low, too.

 

[MrGrumman]

Thank you!
I got this motor at a good price and I need to rebuild my transom anyway so I just double checking that my transom height should be the same as the motor which is 22 in from the bottom of the boat, as well as from the mounting bracket to the bottom of the anti-ventilation plate.

 

[airshot]

Where are you measuring at on the motor ? Should be from underside of the U on the clamp mount to the tip of the cav plate....because the clamp mount sits at an angle on the boat, the measurement could be a little longer than actual. Best way is to hang the motor on a transom or stand and drop a plumb line down to cav plate then measure

 

[MrGrumman]

Thanks!!

I measured from the bottom of the motor clamp on a stand, had a straight edge clamped to the bottom of the anti cav plate, ( sticking out under the stand) and measured pretty much straight down.

I will double check the measurements using your method as well!

 

[MrGrumman]

Thanks!!

I measured from the bottom of the motor clamp on a stand, had a straight edge clamped to the bottom of the anti cav plate, ( sticking out under the stand) and measured pretty much straight down.

I will double check the measurements using your method as well!

 

[MrGrumman]

Im getting the same measurements using both methods. Please see pictures.

 

[thill]

The reason for the extra length is that most transoms are not vertical but are angled and vary somewhat. That way, you don't end up with a motor too short. Better to lift it a hole than to not be able to reach!

Make your transom whatever it was before

 

[MrGrumman]

Well I have mounted the engine to the transom. The anti vent plate is about 3/4" below the bottom of the hill. I'm call that good and a success. Thanks guys for all your help !!

 

[airshot]

Looks good!!