Two weeks ago I was boating on St Clair Lake and hit a wave that pushed the nose down and lifted the props in the air. I was running in the 60's and didnt have a chance to slow the motors. When the stern of the boat hit the water the starbord tach shot up. I was concerend that I had blow the drive. I did not hear any grinding or poping and pulled the lever to neutral. I put the boat back in gear and had engagement on the drive. tried it againg and it engaged again. Tried to get the boat back on plane and it slipped again. I shut it down and tried again this time with success and was able to run the boat 40+ miles at various speed with no issues. Checked the drive oil for any signs of metal shaving and nothing came out. Ran the boat last weekend with no issues and again this today untill the last time when It slipped again. I have a 33 OL with 500EFI's and XR drives. I have had a mechanic check the shifters and adjustment and that does not appear to be the issues, Does anyone have suggestions, I am not knowledgeable enough in this situation but can a coupler slip and cause this? Thanks in advance

Will

As far as I know there are only 2 ways that slip can occur. First is prop slip/cavitation. Second is in a transmission, if you have them. Couplers are basically a solid unit with a rubber center connecting the metal pieces to absorb shock. Sort of like a motor mount. If it breaks, it's broken, period. And even if it was just damaged the first time it wouldn't last long and would have broken the next time out for sure. My guess is you do have transmissions and possibly smoked the clutches in one of them. It might have been weak to begin with and that was the last straw. Try putting the boat in gear with the engines off and see if the props can be turned by hand. If not, please give us some more information on what your driving. Engines, drives, trans. Just my 2 ct's worth.

Sounds like a coupler to me.

Prop hub?

Not as likly with an XR hub

Checked the hub looks normal. I didnt smell burnt rubber as I have read and discussed that it could be when the coupler goes so I am leaning towards the drive somewhere. Going to redrain the drive tonight and see what I get. Thanks for the input please continue with the thoughts or suggestions.

I would guess it's the drive.

When a coupler lets go, it's done.

A friend of mine's boat would do something
similar as what you're describing, he was able
to shift into gear, and it would work ok,
but once he attempted to get on plane,
it would beak loose.

It ended up being a problem in the upper.

+1 on the upper...I'm guessing clutch cone...

Pulling the drive tonight and taking it to the shop. Said they could get to it mid to late this week. Should be back up by the weekend

as a follow up it was actually the shift cable from the motor to the drive. While the drive was off checked the gimble bearing and had a little hitch in it so we are pulling the other drive as well and replacing both of them. Thanks for the ideas and thoughts.

Will