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View Full Version : 2.5 Sportmaster Diaries...Catastrophe averted. Very Lucky I hope



22R
08-06-2023, 08:45 AM
My year 2000ish Sportmaster LU stuck an object (felt like a slight bump) I was doing about 45mph. When I put it back on the trailer i noticed a slight chunk missing on the skeg.

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After home and starting to wash boat I was horrified to see the lower unit was coming off the mid section.

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After removing prop and Ally Foil I found that the mid section rear studs had backed out and was loose. The front nuts was loosening as well but those studs are still tight in the lower unit.
The studs will go back into the mid but seems loose till they get all the way in and then they are solid. I am afraid the threads was damaged by the lossing but not sure if I should do anything besides eiher red loctiting them in or maybe JB weld on the threads ??? Heli Coil ?

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Now as to how his happened. My first thought was the strike but I cannot see that lil bit of skeg damage causing the studs to back out ???
However, in early May I slung an entire blade on my Hoss 28 HD and had to idle back about 4 miles and the engine vibrated badly so I am thinking that is what started the studs loosening?
So 2 questions to you S&F gurus.
1. What should I do if anything to he studs ?
2. on the skeg, should I just grind off the nick and change the sweep of the skeg slightly ? I hate to weld on the lower as it has never been damaged.

any advice appreciated

22R

Tcatrett
08-06-2023, 09:18 AM
Clean up the skeg. Put helli coils , new studs, and lock nuts.

22R
08-06-2023, 12:13 PM
Thanks for the response and advice.

22R

25two.stroke
08-08-2023, 11:18 AM
Pull the lower off and check the mid everywhere for cracks. Most of the ones I've seen loosten up end up cracking the mid. You may have caught it in time to where it didn't. They like to crack right across at the forward pair of studs that hold the lower up. Also check your gear oil for water...lowers usually don't just fall off; especially not from hitting something as small as you did. Either theres some harmonics issue or your studs/nuts just failed. I've seen water though get in the gear oil, skid the propshaft bearing and the vibrations loosen up the lower unit. Crazy stuff happens.