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Lower unit drain screw stripped

Posted: Mon May 16, 2022 3:02 pm
by TDJ2591
Just did our annual cleaning the pontoon for the season today. Only took it out once all last year and the kids used it once. Anyway, itโ€™s now shiny clean and ready to go. Hopefully we can use it more this year.

I changed the lower unit oil. When I replaced the lower screw it suddenly turned easily like it had stripped. I backed it off less than a turn and it tightened up but I feel like it must be stripped (Honda 135hp 4 stroke). Is there any way to repair if stripped? I recall on cars we could buy an oversize self-tapping replacement drain plug. Is there anything similar for an outboard? The kids plan on taking the boat out several times over the next month. I would hate for it to break down and canโ€™t imagine the repair bill if the lower unit goes out.

Re: Lower unit drain screw stripped

Posted: Mon May 16, 2022 7:53 pm
by rbtnt
You can probably use a Heli coil to reapir. Lots of videos on internet on how to install.

Re: Lower unit drain screw stripped

Posted: Tue May 17, 2022 8:26 am
by curtiscapk
+1

Re: Lower unit drain screw stripped

Posted: Fri May 20, 2022 11:41 am
by TDJ2591
Problem solved!

I ordered a Time-Sert stainless steel insert kit (8x1.25x11.7mm) which I found on line. It appears to be far better (and much more expensive) than a Helicoil as it is a solid insert and being stainless will not rust. The kit includes everything needed except the grease I used repeatedly to catch any metal shavings. You drill out the stripped threads with the included bit, tap new threads that are the same size as the outside of the insert, cut a groove the size of the lip of the insert, then screw the insert into the hole using a special tool included in the kit. The tool expands the inner part of the insert to lock it into the hole though I also added red Locktite to the outside threads of the insert. It was easy peasy and stronger, I believe, than the OEM design.

https://time-serts.com/store/m8x1-25-thread-repair-kit/ (Stainless kit is special order and costs a bit more)

Not cheap but far cheaper than replacing a lower unit if the stripped threads failed.

Re: Lower unit drain screw stripped

Posted: Mon Jun 27, 2022 1:29 pm
by Rick McC.
That sounds like a good permanent fix. ๐Ÿ‘๐Ÿ‘