Originally Posted by
Surr
Just added a 6" Vance manual Jackplate to the back of my 97 181 champ. I didn't know about the PTP measurement until I dropped it off to get the work done, wish I would have measured it first. The boat has a 150 merc EFI, with a 23 Tempest, and was mounted 3rd hole down. It would jump out of the water like a rocket and ran great. At top speed it ran right at 5600 rpm. When I picked it up, it is still mounted 3rd hole down on the plate, it seems way to high. So I looked up the PTP measurement on this site and it says 3.5" to start. When I measured it in the garage its 2 5/8", the plate will only come down a little more, but will go up a lot. Should I have the motor remounted down to to top hole, which would drop it 1.5". That would be roughly 4 1/8" and then adjust up to 3.5 and start there for testing on the water. Or does the Jackplate change the measurement. Just spent a lot of money on upgrades, which I will post later, but this is the last item to do to get her back on the water. All your input would be greatly appreciated, thanks.