Mercruiser 4.3 blue drain plug dripping

[bigdogg1]

Good evening, it has been awhile since I posted, but now I am back . Long story short, sold our Striper last summer, lasted about 2 weeks, then bought one that we are really excited. For those of you that remember the best flow diagram ever for buying a boat, we sourced out and bought a Mackinaw 270 from the States last Fall...but that is for another time and story complete with pics etc! Absolutely love it.

But now for the reason of this post. I am fortunate to share another boat with a family member. Fresh water use only with a Merc 4.3 I/O.

Last summer, the very bottom blue manifold valve that one removes to winterize developed a slow drip (~ 1 drip per second while running). This is the bottom plug and I have tried swapping it with one of the others. It seems to be an issue with the female threads as it the only place that drips, regardless of which plug goes where.

This year, I tried a new valve, new o-rings, various wraps of teflon tape and combinations of all of these. The drip continues.

For the mechanics out there, is there a engine-rated sealant (permeates?) that I can use on the valve? They all come out every fall winter so I would prefer not to use something permanent.

Any suggestions would be greatly appreciated!

 

[Reel Gone]

I would bet the casting has a crack in it through the threads

 

[bigdogg1]

Thanks RG. Thought about that option as well. I think i might try a layer of JB Weld directly under the casing to see if it helps.

 

[Pineapple Express]

Nice job on the Mackinaw 270. They have beautiful lines. Looks like such a sweet little big boat. I remember when @turbomack was selling his it was looking very tempting.

 

[turbomack]

Nice job on the Mackinaw 270. They have beautiful lines. Looks like such a sweet little big boat. I remember when @turbomack was selling his it was looking very tempting.

It was a great boat but a little heavy for the launching and retrieving across the beach that i have to do now. My current setup is working well for it's intended purpose.

 

[turbomack]

might be best to remove and braze or silver solder then install a valve to prevent further stress on the casting from tightening the plug.

 

[bigdogg1]

Nice job on the Mackinaw 270. They have beautiful lines. Looks like such a sweet little big boat. I remember when @turbomack was selling his it was looking very tempting.

Thanks! I remember seeing one in person in Vic about 8 years ago. Literally every box for our needs were checked off when I went aboard.

Happened across one in Seattle when I went to a Jays game last summer. Had a hull and an engine survey done and brought it back up on a leisurely 8 hour cruise!

Really happy with it so far.

 

[bigdogg1]

Quick update. Picked up some Marine Tex and ran a small coating under the casting where the valve is. Then, smeared a coating on the valve itself 2-3 times and put it into the threads directly. Left the valve out so the epoxy could set over night.

Ran it for 10 minutes alast night and no dripping. Fingers crossed!