Coolent drain Plug Problem

[Audiofn]

I was working on the boat today and found out that the coolent drain plug on the middle of the boat (Twin engine) Port motor is not installed. We tried to get the plug in but it apears to be either stripped out or corroded out. Is there any tricks or slightly over sized plugs that I can use to fix this?

Thanks
Jon

[MOBILEMERCMAN]

Is it a 1/4 pip plug? The first thing to try is a new plug with teflon tape. The brass wears and the block corrodes.

[fbc25el]

Is it the blue plastic type? If it is I think the thread size is 7/16-14.

[Audiofn]

No this is on a 420hp gen 4. They were brass plugs.

[phragle]

I had that happen on an exh. manifold, drilled it oversized (keep lots of grease on the bit to catch the shards), retapped it next size over and put in a new fitting.

[Audiofn]

I had that happen on an exh. manifold, drilled it oversized (keep lots of grease on the bit to catch the shards), retapped it next size over and put in a new fitting.

That may be what I have to do. Unfortunatly I think that will require the motor to be pulled or at leaste lifted to gain access. Not something I want to be doing before I get time on the boat to see if everything is good to go. Would hate to pull the motor for that then find out it has to come out again for a leak or something....

I did find some expanding plugs that are .375" and that should fit in there. Maybe I could go that rout with some 4200?

Jon

[Ratickle]

I was working on the boat today and found out that the coolent drain plug on the middle of the boat (Twin engine) Port motor is not installed. We tried to get the plug in but it apears to be either stripped out or corroded out. Is there any tricks or slightly over sized plugs that I can use to fix this?

Thanks
Jon

Try re-tapping it first. Not sure what the thread size is, but you should be able to find out and clean the threads that way. Remember just a quarter turn in, then out, then 1/2 in then out, etc. My guess would be just rusty threads first.

[MOBILEMERCMAN]

If the plug is 8 or 10 years old it is worn. Try a new brass plug with teflon tape before you start tapping and pulling things

[Ratickle]

If the plug is 8 or 10 years old it is worn. Try a new brass plug with teflon tape before you start tapping and pulling things

I should always remember, the simplest solution first, always. KISS

[Audiofn]

I am still hoping for the simple solution to work. That being that I can get some stuff out of the way and tap it out and maybe put some tape on there or 4200 if it is a little loose but holding. Other then that one of the things in the picture may work just to get my by for the summer when I can pull it and do things correctly.

[Biggus]

I am still hoping for the simple solution to work. That being that I can get some stuff out of the way and tap it out and maybe put some tape on there or 4200 if it is a little loose but holding. Other then that one of the things in the picture may work just to get my by for the summer when I can pull it and do things correctly.

That's exactly what I stuck in there when we started it on the hose.

We tried a new brass plug, it bottoms out, no threads left. It actually fell right out of the drain hole

[Chart]

Just make sure your bilge pump is strong, and your batteries fresh, and you're good to go. Oh, during long no-wake zones, try shutting that off, and life jackets for everyone.

Steal a boat, and now you want honest advice from those who didn't get your good deal?! humph.

[Ratickle]

Still waiting to find out if the new plug with teflon tape worked.

[cosmic12]

I had this happen on an oldChris Craft 1965. Small block, both center holes were completely rotten no threads at all, I found a couple larger by just a little(metric) brass fittings that had a screw on cap with an O-ring, wish I could find a pic they were about an inch long with 1/2 of that the cap. I cleaned the holes as best I could and put some JB-wield on the threads and put them in and never had a problem and never had to unscrew from the cast iron again. They worked so good I put them on the rest of the motor. I believe they were from large A/C units. For over 6 years all I ever unscrewed was brass to brass. No more problems.

[Audiofn]

Still waiting to find out if the new plug with teflon tape worked.

I will try next weekend when I am back up in Maine.

[phragle]

when all else fails.....

[MERPerformance]

when all else fails.....

I like that! We are talking about a drain plug, go get a metric pipe plug tap the next size up instead of a 3/8 npt or take a 1/4npt clean the threads out and put clear epoxy on the threads and when you want to get it out, put alittle heat on it and break-down the epoxy and wrench it out with a 6 point socket.

[Biggus]

Still waiting to find out if the new plug with teflon tape worked.

The boat's up here at my house. I tried a new plug, the threads are so far gone when you try to get it started it bottoms out into the hole. It fell right out.

We'll try a larger plug.

[Geronimo36]

If nothing else works, how about an oversized plastic plug instead? No need to re-tap the plastic will form its own threads and seal it the more you tigheten it up???
http://www.product-components.com/pipe_plugs.html

[Audiofn]

Ok I got it fixed this weekend. It was PITA!!! I had to take off the manifold, tranny oil cooler, fuel filter, water pump....... Once I got all that done the repair was easy. I ran a tap back into the hole. The problem was that the hole at the outside of the motor was all opened up and no threads. Deeper into the block there was still some threads. The plug could not reach those threads. So what I did was get a 1/4" NPT Brass pipe about 1 and 1/4" long and threaded that into the block after tapping it and it bit very nicely. Then I took out the pipe and put JB weld on it for added support were the block was corroded. It should be super strong. Then I just put a cap on top of that. It fits very well and should not make it any more difficult to drain when needed.

Thanks for the help guys.