[quote=svrootless]We tried her 2 times about 2 weeks later for a very short period of time (about 5 seconds each) ... [/quote]
If you've only cranked 10 seconds in total, I wouldn't be too worried.  Now that you know about the glow plugs switch, I'd give it one more try -- but only after making sure to use the glow plugs for maybe 30 or 40 seconds.  If it doesn't start after about 5-10 seconds of cranking, then yes, you'll should drain the muffler to clear out the accumulated water, before you try further cranking.  

[quote=svrootless]  ... The helm says to drain the aqualift muffler. We attached pics of what ours looks like and it appears the valve is broken. The screw that is sticking out is a hole that stops at the fiberglass area but I cant see a way to get this to drain. The wing nut looking thing is literally doing nothing and has rotted. The engine area itself has no visible signs that there has been water in there as there is blue dust, white dust and engine paint chips. Can any of you look at the pics and tell us how to get this to drain? Dana and Scotty Gillette 1997 Catalina 36 MKII Rootless (Hull # 1624) Tacoma, WA Purchased in Sept 2016[/quote]

Your 2nd and 3d pictures seem to clearly show the drain valve (looks in about the same condition as ours!).   The valve looks sufficiently intact to operate.  What do you mean it is "literally doing nothing."? Have you attempted to unscrew it?
You should be able to unscrew the entire assembly, if needed, so that the water drains out. 

Catalina Direct has replacements ( www.catalinadirect.com/index.cfm/product/1932/aqua-lift-muffler-drain-valve.cfm ) for about $12, pictured below. (If you end up removing the entire assembly to drain it, and the thing disintegrates, I suppose you could just temporarily thread a bolt in there as a plug while you wait for a replacement to be shipped.)
 

Yours look like mine. I have never tried to open it. I would agree with Matthew that you could remove the whole fitting. You could just put it back in after draining. If it NG than i guessing a pipe plug would work, It's maybe 1/4 NPT. Just take it with you to the store to match size. It won't measure 1/4.
Another way would be to loosen  the "hump" hose. If no water is coming out at the hump hose then the muffler is not over full. The hump hose is in your last photo. Looks like you have a black one. 
A very good mod is to change this hose to the new "Blue hump hose"

I have never had to open this valve. Some valves must be turned clockwise to open. Can someone else confirm its rotation direction.

get on the drain with some penitrating fluid and a wire toothbrush -- it will turn into the muffler and water should come out the center.

Sounds like a common problem, our boat had the same issue when we bought it. Purchased a new one from CD and used a vise grip to remove the corroded fitting. It disintegrated but came out without leaving any bits in the muffler. The new fitting threads into the muffler, use pipe dope or teflon tape on the treads. When functioning properly the fitting body stays stationary, turning the wings CCW will allow water to drain out the center hole.