Lower unit stripped drain plug

[knarfztnark]

I have a 1989 Evinrude 175hp. Due to 30+ years of lower unit gear grease draining and filling, the bottom drain plug thread is stripped. I thought I might oversize and retap the hole from 3/8×16 out to 10mm. Does anyone know of a resource for an oversized drain plug that might work. Thanks

 

[ThomW]

Most local hardware stores have a rather large selection of various "drain" plugs in stock. I would go check that out, then tap your hole according to what you find, rather than tap it and try and find one to fit. Just make sure you find a gasket/washer to go with the new plug.

 

[saltchuckmatt]

I'm not really good at putting them in but I wonder if you could put a heli- coil in.

 

[Scott Danforth]

I would helicoil it

 

[racerone]

Helicoil is one option.-----I would make a new plug with a hammer and chisel.------Hint---Buy a 10 mm bolt.----File the head round.----Use hacksaw and fine file to put a slot in it.

 

[airshot]

Have this a few times....get a shoulder head bolt with a bigger thread, then turn/ grind the head dia to match the existing head dia. Retap the thread to the new size, make a new gasket or find a fiber washer, flush chips from the retap in lower unit. Screw in your new plug.. being a toolmaker was probably to my advantage, but not hard to do...

 

[1960 Starflite]

1/4" pipe plug. Internal hex would be my choice.

 

[clemsonfor]

There several good solutions here. I would do what the guys said. I'd look in a box of stuff at lowes or TSC. See what kind of cap screw you can find. I'm sure there is something very close in size that would work.

I am not sure if a Helicoil would work as you don't have that much meat to put one in and they usually have a certain size they can fit, but maybe there all different depth Helicoil? The ones I used were just a certain size for the thread pitch you were using.

 

[Chris1956]

At one time there was a fitting just for this purpose. The hole was drilled and tapped, and a repair plug was permanently installed. The repair plug has a standard gearcase plug in it. Not sure what the name was. Likely a Mercury product.

 

[airshot]

At one time there was a fitting just for this purpose. The hole was drilled and tapped, and a repair plug was permanently installed. The repair plug has a standard gearcase plug in it. Not sure what the name was. Likely a Mercury product.

Now that you mention this, I recall seeing something likevthat some years back !! No idea if they are still around, but well worth looking into......

 

[Crosbyman]

outboard drain repair - Search Videos

www.bing.com

 

[cdfor3]

I have a 1989 Evinrude 175hp. Due to 30+ years of lower unit gear grease draining and filling, the bottom drain plug thread is stripped. I thought I might oversize and retap the hole from 3/8×16 out to 10mm. Does anyone know of a resource for an oversized drain plug that might work. Thanks

My dumbass stripped the threads on a brand new Suzuki Df60A. I was about to bite the bullet and purchase a new one until I found a timesert in 1.25 mm fully threaded with a counter sink option. It was pricey but got the job done. I barely ended up creating any shaving when I tapped it. Was able to use original plug and gasket and has worked. I did flush with and let sit on some sacrificial oil just to get any shavings out the tap grease didn’t catch. Find one of these yall! But never ever use heilcoil! You will never get a proper seal !

 

[cdfor3]

My dumbass stripped the threads on a brand new Suzuki Df60A. I was about to bite the bullet and purchase a new one until I found a timesert in 1.25 mm fully threaded with a counter sink option. It was pricey but got the job done. I barely ended up creating any shaving when I tapped it. Was able to use original plug and gasket and has worked. I did flush with and let sit on some sacrificial oil just to get any shavings out the tap grease didn’t catch. Find one of these yall! But never ever use heilcoil! You will never get a proper seal !