86 supra comp prop shafter coupler

[nbiffle]

hi guys i have always owned a outboard motor but i just bought this inboard supra. The other day I was running my boat and i went to take off and heard a whistling noise. So i shut her down and went to the coupler was and saw that it was spinning on the shaft. after i seen that i was towed back to the boat ramp. When i got back to the house i took it apart and saw the key was missing. the only thing on there was the set screws. Do i need to put a key back in it or can i just use the set screws. any help would greatly be appreciated. thanks nathan

[chris young]

You most definitely must put in a new key. I don't know which one you have, but even the lower hp motors in these boats are 240, and a load of torque. I doubt very much you'd last more than an hour of heavy use before you sheared the set screw off. While you're at it, in order to replace the key, you'll need to disconnect the coupling from the transmission, so it's a good time to properly align the motor to the shaft.

Take 15 minutes to watch this video, it explains shaft alignment really well http://www.youtube.com/watch?v=3_w0LvD6gEc

Welcome to the site Nathan, which boat did you get?

[chris young]

Oh, and while you're at it, you should check that the prop key and the cotter pin are there as well. If someone had the shaft apart and put it back together without putting a key in, lord knows what they did below. Mine had no cotter pin, and over the course of about 15 hours of skiing use, the nuts disappeared, the key disappeared and then, the prop disappeared. I've actually got an old photo of the boat that the PO posted when it was for sale, and you can clearly see the cotter pin is missing. It was totally my fault I lost the prop, I should have checked.

There are some good articles on the net on lapping a prop for a proper fit, as someone pointed out here a few months back it's not the key that holds the torque it's the taper on the shaft. Some shafts are tapered at the coupler end as well, so I would assume that lapping that end would be a very good idea as well.

[nbiffle]

Thank you for the quick reply, the video really helped me. im pretty mechanically inclined so i did the work my self. my boat is an 1986 supra competition wakeboard boat. it was garage kept and is immaculate condition is 775 hrs on a boat like that alot for that year model and it has a ford 351 windsor.

[chris young]

I think you mean competition ski boat. Glad to be of help. TS6M Comp is Tournament Skier 6 metre.

Cheers

[Ptownkid]

Chris...check your messages

Sorry to hijack boys, carry on.