1988 15 hp Johnson gearcase drain plug problem

[ace1]

I got a small problem. I drained the gear oil with intension of replacing it with new. We I got ready to install the botton drain plug it would not tighten up!!. The gearcase housing threads are stripped out. Any idea what size threads this is? I had in mind putting a helicoil in it but i dont know what size to get so the original drain plug will work. thanks

By the way, I beleive the part number for the drain plug is 0307551 if that helps.

 

[F_R]

Re: 1988 15 hp Johnson gearcase drain plug problem

3/8-16 The tricky part is going to be getting it straight. If not straight, the plug head will be tilted too much to get a seal.

 

[ace1]

Re: 1988 15 hp Johnson gearcase drain plug problem

Anybody else come accross this and if so what did you do. Im just looking for some suggestions or ideas.

 

[F_R]

Re: 1988 15 hp Johnson gearcase drain plug problem

I'd say proceed with what you have planned. I've seen cases where somebody has drilled and tapped it for a pipe thread and made a slotted pipe plug. Certainly not my preference, but better than scrapping the gearcase. I suppose it would be a last ditch option if you totally screw up the Heli-Coil.