Water Plug unable to be unscrewed

[summerwind]

I have a Mercruiser 350, and one the blue water plug's wings on the "blue wing nut" have cracked off while unscrewing with a plyers. Any ideas on how to remove now. Maybe Vice Grips? One related question. The two water plugs underneath the engine are very hard to reach to remove but are much harder to locate in the spring, when the plugs need to be put back in. Any ideas on how to mark these two plug holes so they are easily to locate in the spring. I thought maybe a 'pipe cleaner' stuck up there that would block the hole but would be easily identifiable, but they fall out easily.

 

[littlebookworm]

You can try vise grips, and if that doesn't work, if there's room, drill out the center of the plug and use an 'easy-out' to remove it. I have a feeling you're over-tightening the plugs when you put them back. As to the hard-to-find plug locations - try laying a mirror down and using it to spot the holes. Obviously, you leave everything open and dry, rather than filling with antifreeze. That's a debate that's been going on for quite a while. However, when you leave plugs out, the threads will rust slightly over the winter; usually just enough to make screwing the plugs difficult, if not impossible. The recommendation I've seen is to put the plugs back immediately so the threads in the block or manifolds don't rust. Make sure you use the correct O-ring on each blue plug to seal the opening without having to over-tighten the plug. Hope this helps. Hy

 

[Stephen]

My advice is to replace those blue plugs every three uses (years for me). I also use tef-gel paste on the threads to prevent corrosion.

 

[jlee815]

Can't help you with the busted plug but those plug threads for me last a season or 2. Three is pushing it. I always keep spares around now when winterizing.

 

[TIMEOUT90]

Vise grip could work. I've snapped a few off before where there is nothing sticking out but the threaded end of the plug is still in the hole. My easy solution is to cram one tip of a needle nose pliers into the hole in the plug then spin it out. Just used that trick on Wednesday, worked great.

 

[summerwind]

Thank you for the info. I tried a vice grips and the top broke off. leaving the blue plastic in. fortunately this plug is at the top of the engine. The 3 below I have removed and drained. Quick question, If i drill or use needle nose plyers,and plastic breaks off inside,do small plastic shaving or shavings inside cause a problem?

 

[LouC]

I'd see if the plugs could be replaced with a metal plug of the correct thread size and pitch. I have the metal plugs in my old 88 OMC and never had any issues with removing them. I put OMC gasket sealer on when reinstalling and the always come right out evev with salt water use. Plastic plugs are not one of Mercs better ideas.....