PSI Gauge install on 2.0 Merc

[Glenn]

Putting in a 30 PSI gauge on a '78 2.0 Merc 175. Looks like I got to remove the plug on top of the block just behind and under the flywheel a bit. 3/8 th ratchet fits perfect in it. Problem is it looks like it hasn't moved in 24 years and it doesn't want to either. I haven't REALLY tried applying force to it yet. I'm worried maybe the aluminum casting around it will break or it will pull some threads out with it. I'm aware of the corrosion effects of dissimilar metals. Should I try and heat it, just reef on it, or throw an impact gun on it? Glenn

[Techno]

Get some Kroil from Kano industries. It's a penetrating oil that will sneak in the micron(millionths of an ") size gaps. It really does work.

[Glenn]

Thanks Techno. I'll clean the paint off the exposed threads of the plug and give it a try. I'll give it a few days to really sink in and work. Not anxious to bust the block before I even get the boat in the water! Glenn

[Rickracer]

Try a little heat (propane, not acetylene), then Tap (not bang) on it with a hammer. Let it cool, use your penetrating oil again, then try again.

[Glenn]

Thanks guys. I Let it sit for a few days with some penetrating oil. Gave it a quick shot with the impact and it came out no problem. Now, on to the temp gauge....

[sosmerc]

It might be easier and safer in the long run to just drill and tap that plug for an 1/8 inch pipe thread. Then you can install a brass barb of the appropriate size for the water hose that you are going to use. If you are installing a new Merc water psi guage I believe they now come with a new type of flexible hose and numerous brass fittings to choose from. They now use a quick-disconnect system for the hose.
Once you figure out how to use it they are pretty slick.
Good luck on your project.

[Mark C.]

Techno -

Do you know if there someone in the Rochester area that handles Kroil?

Thanks