Twist valve?

Started my 1988 4.3L Mercruiser today only to find out it was idling VERY rough and shaking violently. Had it winterized by a pro last fall so I assumed all would be turn key, wrong! I started looking around the engine and found that a plug wire was just sitting on the cap, not properly seated. Also on startup the engine let out a squeal. At first I figured it was the alternator under load, but the belt seems loose and is pretty worn so I changed that as well.

Now for my question. When looking around I noticed a little blue valve right above the front starboard motor mount. Any idea what it is for and should it be turned?

The hose from the valve runs here.


Thank you!

Re: Twist valve?

That is drain plug for winterizing.

Re: Twist valve?

The blue wingnut is a drain valve. There are 4 or 5 on your engine. That is where the water is drained from the engine and the manifolds during winterization.

As far as a plug wire being off. It probably got pulled out during winterizqtion. Put it back on. When an engine is fogged and drained, there is no way a dealer can test run it to make sure everything is ok or he would have to winterize it again..

Re: Twist valve?

I appreciate the info as always. Still learning all about my "new to me" boat.