How do you know when to replace the coupler? I haven't had any issues, but I'll be pulling the engine this winter and wondering if it's time?? It would be an easy fix while the engine is out, but then again would it be a waste of money? Thanks!

Take a look at the splines. If they are tapered and come to a point (like a chisel) they are worn. If the taper on the splines have a flat edge you are good to go. Also inspect the input shafts for the same. Inspect the rubber dampener that the spline hub is in for any deteration also.

What engine? Most new mercs have the race coupler. I know the older motors had alot weaker coupler. I've seen them go out with less than 150 hours because of neglect.

The key is to keep grease on the couple. I grease mine once a year when I winterize. I use Amsoil syn marine, Merc spline grease is good also. A dry spline will wear very quick. I have 500 hrs on mine, still working fine.

Not to get off topic but I think I saw you at the Kaskaskia a couple of weeks ago. On a Saturday the day it rained half the day. I have the 236 Baja, be sure to stop if you see me tied up in Evansville.

Yea we were there. We spent the day in New Athens waiting it out. I had the boat home for a few weeks.