an engine coupler is made pretty much the same way a prop is with a rubber hub pressed in and yes it will slip as they start to go much as a clutch slips in a car or a prop hub will slip



have seen it many many times



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Update

Took the boat out of the water and removed the prop. We noticed the prop wasn't tight tight but it was secure. Put it back in the water, WOT no problems. My first thought was, WTF!? LOL! What should I do now?

Drive it till it breaks

what he said

yessssssssssssssss

LOL

I plan on it now.

One possibility, speaking from own experience , the prop may spin out when you come off plane because the drive is still trimmed out for high speed. I my case I thought the drive was shot but it was only the prop ventilating because of the high trim.

One thing I was told it might be is Clutch cone in the outdrive. Any comments?

I think you should still replace the coupler just to make sure ....

It wouldn't slip like you described. It would either go into gear or it wouldn't.

Check the vetilation / trim possibility before doing some expensive repairs. Mechanical failures are very seldom intermittant.