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

Ttt

Can you get access to see if any of the threads can be saved with a pipe tap ??
I wonder if anyones makes a self tapping pipe plug ??

Driil & helicoil ??
The cast metal doesn't drill so well tho..

If not, just an idea.
Clean the hole smooth and use one of those rubber expandable plugs.

All things that I have been thinking about today so either we are both crazy or both onto something that could work....

The problem is that it is on the inside plug of course between the two motors and there is a coolent hose that is for the tranny cooler in the way. I hope that when it is a little warmer I can get down to my shirt and slide down into the bilge and get a better view. Biggus was able to get his hand in there but I was not.

I have spent a bunch of time looking for a oversize pipe thread maybe metric?

Maybe try a plastic or composite plug.

what motor is this ?

This is a stock 420hp Mercuiser in the 311 that I just got. They left the plugs out for 9 years.

If you can't chase the threads with the orginal 1/8 pipe drill and tap for 1/4 pipe. thats what I did with mine. Then installed small 1/4 turn valves, makes draining alot easier in fall.

Think this was posted on Serious Offshore, Either go to a metric pipe thread or run a 1/4 npt to clean it out and use some clear epoxy on it and when you want to remove it use alittle heat and back it out with a 6 point socket.

John, get down in close as you can with a mirror and a decent light so you can see what your up against. get a small dremell tool wire wheel and clean it up as best ya can. then go up to the metric or oversize it as others have suggested. tight quarters suck,but some times ya just have to get stuff out of the way. say hi to kurt for me. good luck J ps maybe pull 1 exhaust manifold ? all the others took thread ?