Jackplate Issues

thull

Petty Officer 2nd Class
Joined
May 26, 2012
Messages
142
Hi all, I made a jackplate for my 1983 25hp evinrude because it was roostertailing and almost -3" from the keel to anticavitation (AC) plate. It's 3" angle AL. After installing, I set it high at first (AC plate was 1" above keel). However it was cavitating and not getting on plane like it did prior to jackplate. So I lowered it down to AC plate even with keel. It got a little faster and almost on plane but still needs to drop a little I guess. Problem is, the thumbscrews are hitting the front of the plate now. They overhang the front of jackplate by 5/8". My question feels stupid, but do I need to decrease my mounting board thickness to get the thumbscrews to clear the front of jackplate or increase the thickness? I have plenty more than 5/8" of thread to play with inside the jackplate, from the outboard mounting bracket to the mounting board, and the thumbscrews will fit inside the jackplate if I can adjust the mounting board thickness in the right direction. See photos below. Geez that's long-winded. In short, does the board need to be thinner or thicker to screw in the thumbscrews more to get them inside the jackplate?
IMG_20201022_192144296_resize_55.jpgIMG_20201022_192125259_resize_40.jpgIMG_20201022_192211717_resize_27.jpgIMG_20201022_192158141_resize_93.jpgIMG_20201022_192213123_resize_22.jpg
 

froggy1150

Senior Chief Petty Officer
Joined
Nov 3, 2017
Messages
796
Here is an idea......
Remove thumb screws and use bolts. You would have ti keep a wrench handy to adjust
 
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