Stripped lower unit drain plug

[1luckydad]

I have stripped out the lower unit drain plug threads on my 2003 Yamaha. I am contemplating using a helicoil for repair. I am just wondering if there are any other alternatives or advice out there before I tackle this problem.

[Surface Tension]

1luckydad, can you get a helicoil that size? Drilling and tapping would be a permanent fix. Biggest obstacle I see is keeping the filings out of the lower unit after its been drilled then tapped. If you can lay the engine on its side so the drain is pointed down as you drill and tap you would minimize most if not all the filings. Maybe at the same time you could blow compressed air through the upper vent. Finish up with a flush with fuel oil.

[Fisher Dave]

Yes, there are helicoils of that size.. but I wouldnt do it.. as ST said, the metal shavings #1.. on the other hand.. I dont think it would seal properly and it would cause some problems in the future.

If anything.. drill and tap it one size larger.. you may want to run a tap of the same size and see if the threads clean out and it holds.. it would save a bunch of hassle if it worked.

I have had problems with bolts loosening up in helicoils.. that is the last thing you want on a lower unit drain.

[upnorth]

I wouldn't worry too much about aluminum filings in you lower unit. Aluminum is very, very soft compared to the hardened steel in your bearings. I would drill and tap it blow it out and then flush it with fuel oil or some other thin oil. Anything left in there will will just get pulverized running through the bearings.

[1luckydad]

Thanks for the responses. I think I will look into just going to a bigger size instead of the helicoil. I believe I messed it up by using my impact on it, as I didn’t have a big enough screwdriver to do it the proper way. I have now learned my lesson and purchased a big enough screwdriver. One can not have to many tools.