Stripped exhaust drain plug threads

[Cloaked]

Originally Posted by blakekrone

Quick update, was a nice day for a drive and I haven't towed the boat yet any distance so I decided to run up to midwest mastercraft. They checked it out real quick with their tap and said that should work so I ran around looking for a 3/4" tap, finally found one and now I'm good to go it appears. Should know tomorrow when I start it up.

Hoping to hit the lake for an hour tomorrow night just cruising.

Use Never-Seize when you put the new plug(s) in...

[88 PS190]

Agreed, I've been planning this same project just to get more threads engaged, mine only thread in about 1.5 threads.

[Cloaked]

Originally Posted by 88 PS190

Agreed, I've been planning this same project just to get more threads engaged, mine only thread in about 1.5 threads.

I'll say this (as I have many times before)... a few threads of engagement is OK, just whatever it takes.

I put my plugs in expecting them to leak and while watering the engine, I tighten the plugs only to the point that they no longer leak. Stop, not one more turn..nothing... the plugs will be fine and stay there until wrenched back out....

Been down that road and those threads will easily strip. Just tighten enough to stop the leak...

.

[Ski-me]

OK, I now also have the same problem. I'm trying to determine if the 3/4 NTP is the same thread size/pitch as the 3/4" galvanized plug at Lowes (or the 3/4" gas black pipe). The threads line up with my old plug. I just want to make sure before trying to get these one.

I couldn't find a brass fitting (tee, reducer) to match the same thread pitch. The ones I found were more coarse.....like a hose type thread. I saw a lot of MIP type threads, but no NTP's.

Does Lowes/HD have a 3/4" tap this size? Is it a common one?

[j.mccreight@hotmail.com]

Originally Posted by Ski-me

OK, I now also have the same problem. I'm trying to determine if the 3/4 NTP is the same thread size/pitch as the 3/4" galvanized plug at Lowes (or the 3/4" gas black pipe). The threads line up with my old plug. I just want to make sure before trying to get these one.

I couldn't find a brass fitting (tee, reducer) to match the same thread pitch. The ones I found were more coarse.....like a hose type thread. I saw a lot of MIP type threads, but no NTP's.

Does Lowes/HD have a 3/4" tap this size? Is it a common one?

NPT (national pipe thread) is what you need, yes any big box store should have the plugs and taps.

[Footin]

I had the same problen a few years back, I chased the threads with a 3/4 NPT tap then installed 1/4 turn ball valves on each side. Now when I winterize I just turn the valves to drain, no more removing the plugs.

[blakekrone]

Originally Posted by j.mccreight@hotmail.com

NPT (national pipe thread) is what you need, yes any big box store should have the plugs and taps.

On the contrary none of the big box stores here in my area had NPT plugs nor taps. I ended up getting plugs from the local MC dealer and Northern Tool had a tap set that included the 3/4" I needed.

[j.mccreight@hotmail.com]

Find a sears hardware, they should have them...

[JimN]

Originally Posted by Ski-me

OK, I now also have the same problem. I'm trying to determine if the 3/4 NTP is the same thread size/pitch as the 3/4" galvanized plug at Lowes (or the 3/4" gas black pipe). The threads line up with my old plug. I just want to make sure before trying to get these one.

I couldn't find a brass fitting (tee, reducer) to match the same thread pitch. The ones I found were more coarse.....like a hose type thread. I saw a lot of MIP type threads, but no NTP's.

Does Lowes/HD have a 3/4" tap this size? Is it a common one?

Look at a piece of threaded black pipe- the thread is tapered, to ensure a good seal when it goes into a fitting.

Go to an ACE hardware store- they have a set of sliding panels with bins, filled with brass fittings.

[Ski-me]

Originally Posted by JimN

Look at a piece of threaded black pipe- the thread is tapered, to ensure a good seal when it goes into a fitting.

Go to an ACE hardware store- they have a set of sliding panels with bins, filled with brass fittings.

So, if it's tapered, will a 3/4" -14 tap work to clean out the threads?? I'll check out Ace today if I can break away......

The plug I pulled out matches the black pipe but whose to say the old one is correct. I guess I'll have to assume it is after all these years.