Jack Plate Questions

USMC1989

Cadet
Joined
Oct 17, 2012
Messages
12
'Evening, Gentlemen-
I have what I believe may be a stupid sounding question, but bear with me. I'm in the process of restoring a '64 Mirrocraft runabout & have some questions about jack plates. The transom is approx 16", the motor is a 1965 Evinrude Big Twin 40hp. It is the original motor that came with the boat. The previous owner said the boat topped out at 20mph on gps, which seems very slow for this boat/motor (had a previous thread regarding this). It was suggested that perhaps the motor wasn't running as well as it should. I've been doing some reading on the differences in performance that motor height makes & have been doing a little research on jack plates (manual, not hydraulic/power plates). Here's my stupid question - the jack plates I was finding all seem to be set up to LOWER the motor, not raise it. Looking at the motor mounted on my boat, I think that the motor would need to be RAISED, if any adjustment was needed at all. Not much, possibly only by an inch or so. Do you guys know of any good manual jack plates that are for adjustments either up OR down? I was looking online at the Vance jack plates, they seem to be nice & are reasonably priced. However, if mounted even with the top of the transom, they would only move the motor DOWN FURTHER (unless I was misunderstanding the info given & pics of the product).

Thanks in advance for the help!
 

USMC1989

Cadet
Joined
Oct 17, 2012
Messages
12
Re: Jack Plate Questions

One more quick question - being that the motor is the ORIGINAL that came with the boat, wouldn't it be matched properly as far as height goes?? One would think that this is the case, but............
 

Mi duckdown

Commander
Joined
Apr 14, 2007
Messages
2,575
Re: Jack Plate Questions

USMC. Pics of motor in relation to the tramsom would be Very helpfull. Back in those days transom heights were fickle, and the water pickup on those motors was also. PICS.
what are you trying to acomplish, more speed? Are you also sure the motor is in top running condition? this all needs to be addressed.
 

Mi duckdown

Commander
Joined
Apr 14, 2007
Messages
2,575
Re: Jack Plate Questions

Oh ya. you could easily put a piece of square alum stock between the clamp and transom. to find out.
 

Bamaman1

Lieutenant Commander
Joined
May 15, 2011
Messages
1,895
Re: Jack Plate Questions

Jack plates can be to raise a motor or lower one. Most I've seen are on high horsepower boats, like bass boats, to get maximum top end speed. They can also be used to helpo correct handling problems.

But to put all that time and effort on such an old boat is overkill. You should put your energy in getting that motor running as good as it can run. Every boat and engine have inherent limitations, and sometimes we've got to accept them as they are.
 
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