I was wondering if any of you guys that do your own work on your outboards have ever run into anything like this. I have a 5hp seaking/john/evinrude 1956, but that isnt the problem. My buddy, doesnt know much at all about outboard motors just got a new 1957 12hp seaking. The motor runs perfect, and it waters good and has newer coils, so everthing on the top end is great. When we put it on my boat and launched it for a test run, everthing seemed fine unitll it slipped under higher rpm. It doesnt seem to slip in reverse, and in forward it hooks well enough to make it plane out, but once you open it up a little more it lets go, rpms go up and boat slows. I turn down the throttle and it hooks back up, and you can repeat the above untill it slips out again. I was wondering if there is a clutch in the drive somewhere in the drive shaft. My parents had an evinrude tri-hull v8 with an omc outdrive and it had a clutch that slipped out in the lower unit. We were able to switch it with the reverse clutch, since you never really go full throttle in reverse. I was hopeing that his might be the case. I'm picking up a manual today after work so that will probably help make things clearer. However, the only outdive I ever saw the inside of has been tha big omc. Any insights or tips would be appreciated.