Motor height question

[snowman48047]

My cousin's boat, a 79 Starcraft Mariner with a 40hp. The motor has clamps but also 2 bolts below the clamps for attachment to the transom.

I think he has the motor maybe 1.5 inches to low. The 2 bolts are only through the aluminum below the transom board. I think it should be higher so the bottom bolts actually go into the new plywood. Thoughts? Having trouble with pics on phone... the flat plate above the prop is probably 2-3 inches below the line of the hull.

 

[sheboyganjohn]

The anti cavitation plate on the motor should be even with the bottom of the boat. If the motor is in the correct location you can always add a backer board inside the boat to spread the load of the bolts.

 

[sphelps]

Yep the vent plate on the motor should be pretty much even or within and inch of the bottom of the hull .. Just a tad above the hull is ok also from what I have read ...

 

[gm280]

[QUOT,E=sphelps;n10258297]Yep the vent plate on the motor should be pretty much even or within and inch of the bottom of the hull .. Just a tad above the hull is ok also from what I have read ...[/QUOTE]

Yes, sphelps is absolutely right, it is amazing how even an inch change in height can change the entire operation of an OB. I used a Jack-Plate on one of my boats and the boat came alive with that option. I was sitting too low and the difference in drivability and speed was an eye opener.

 

[Woodonglass]

This should be helpful...

 

[snowman48047]

No Title

Here is a pic...

 

[snowman48047]

No Title

 

[gm280]

snowman48047, without being there to see in person, I'd say just by the picture you provided, you are sitting too low. JMHO!

 

[snowman48047]

No Title

Here you can see both lower bolts. I think they should at least be in the metal...you can see where they were before the transom was replaced.

 

[kcassells]

Here's a good link for read;
http://media.channelblade.com/boat_...s/dts/dealerlibraries/8441/copetipstricks.pdf

or
http://propellerhub.com/engine-heights.html