Stripped Lower Unit Drain on BF90 Concerns

[JStauf]

Hello, looking for some good advice. I stripped one of my top drain plug holes on my Honda BF90 lower unit. I've already bought a Heli-coil kit and have installed them previously in other situations. I know I need to shorten the heli-coil for this application.

My BIG concern is removing the tang from the heli-coil without losing it in the lower unit, requiring a nasty fishing trip that may result in a teardown of the lower unit. ANY advice from anyone who has "been there" is appreciated.

Thanks in advance!
John

 

[gm280]

Are you certain a heli-coil will work in that area? Not knowing the area you're talking about but only visualizing my setup, that area is pretty thin material. However, maybe some magnetic or even a wire wrapped very tightly around the tang before breaking it off could work... It would hold on to the tang securely and after breaking it off, allows you to pull it out without any problem... Just a thought...

 

[robert graham]

Might be a good idea to have the Helicoil Installed by an experienced marine/outboard mechanic.....so not to risk a screw-up in this critical area.....

 

[JStauf]

Hi guys, thanks for the response. I may not be an outboard mechanic but I am a certified aircraft mechanic who has always worked on my own outboards. This is a commonly Heli-coiled thread hole (from searching the web) and I even spoke with a mobile mechanic in Key Largo recently that says he regularly makes this repair but I forgot to ask him about the Heli-coil tang. The Heli-Coils are made of stainless steel, so a magnet is not effective for retrieval.
Appreciate advice from someone who has done this repair.
Thanks

 

[gm280]

JStauf, I use to install smaller size Heli-coils when I worked DEPOT maintenance many decades ago myself. But you stated that you do that on aircraft repair. so you also know how to use safety-wire pliers as well I'm sure. If you took some fine gauge safety wire and used the safety-wire pliers and twisted that wire around the tang either before or after installing it, then you could snap off the tang and pull it out with the safety wire ends... Seems like that would work.

 

[steelespike]

Stainless with high knickle content is not very magnetic but lots of stainless has a pretty good attraction.

 

[JStauf]

gm280, interesting idea. A tight piece of safety wire around that little tang before I punch it in. It ought to work, I think, as long as I get it tight enough, but I'm sure concerned I might knock the wire off when I strike it.
Sure was hoping someone who does this repair would chime in. I think I'm going to try and get a hold of the mobile mechanic in Key Largo and see what his method is. He says he's done quite a few of these. If I can find him I'll post it here.
Steelespike, maybe, but I've personally not seen a piece of magnetic stainless steel yet.
Thanks for the ideas and thoughts

 

[gm280]

JStaut, how deep is the tang going to be after you install the heli-coil? The reason I ask is because if it isn't too far in, a good quality needle-nose pliers or even a locking needle-nose vise-grip long nose pliers could reach it to snap it off and pull it out as well... Just another idea... Let us know what you do and how it works out.

You could always fill the hole with some grease prior to installing the heli-coil so if the tang does snap off it will simply be in the grease instead of falling down into the lower foot area... The small amount of any type grease will never hurt anything either.

 

[isaksp00]

Would it be feasible to leave the tang in place? I am not sure how deep the threaded plug is, but if it is not as deep as the depth of the tang (my small Honda has a rather shallow plug), and all you expect is that oil drains out of the top hole when you pump the new stuff in, would it cause any problems just to leave it?

 

[JStauf]

Called Dean the mobile outboard mechanic at Garden Cove Marina in Key Largo today.
He has done many of these drain plug helicoils.
He says he just uses needle nose pliers.
So I'll do the same! Thanks for the comments and ideas, should have just tracked him down sooner.
Gm280 you figured this one out.
Isaksp00 he said he has left the tang, but you have to be real careful about clearance with the gears.