muffler draining

[Ken Heyman]

Yesterday, we had an engine failure on Lake Michigan. Fortunately we had the redundancy of "sail" as I store with the mast up. At any rate upon trying to restart the engine after bleeding the system I may have cumulatively cranked the engine for more than 30 seconds. (I did not get is started) Do I need to drain the muffler before retrying. My plan is to change my filters today and trouble shoot the fuel system. Pretty sure that I am once again looking at gunk in the system. I know there is much info on this subject so I wanted to confine my question to the muffler issue. Is the drain a butterfly valve at the bottom. If so I'm afraid that it may break if I put much pressure on it as it is corroded. Last year I tried some anti seize lubricant but to no avail.

Thanks in advance,

[Stu Jackson]

Ken

If you're over 30 seconds, you NEED to drain your muffler.  Keep using liquid wrench, better yet get a can of PB BLASTER.  If you use the PB it'll clean that little butterfly handle valve in no time.  Compared to Liquid Wrench, it's like night and day.  Good hardware stores should all have it.  Not a marine store: too pricey and they may not have discovered it yet (even though it's been around for awhile).

After one or two applications, try a wire brush on the threads (bronze, not steel to avoid rust in your boat).  Then keep applying.

You MUST do it, or risk backing water into your engine.  

You could also consider trying to get it started with the raw water thru hull closed.  This will avoid more water getting pumped in by the rw pump and into the muffler.  Need to be quick to avoid damaging the pump impellers, but you were good and ready to replace it anyway, right?  The engine won't overhat for a few minutes so you have time to get the thru hull opened again.

A little patience or a new engine.  Your choice.

[Roc]

If your butterfly wing nut is corroded, maybe you may want to replace the whole part.  On my muffler, the on/off wing nut is threaded into the fiberglass muffer, with teflon tape on the threads.  Looks to be an easy R&R excersise.

[Ron Hill]

Ken : I'll guess that if you did backup water into the engine (too much water in the muffler) that it's already done.  
It maybe easier to replace the entire butterfly drain valve if your's is frozen.  If you have a hump hose you can remove it and suck most of the water (black and nasty) out of the muffler that way and not screw up your bulge.
As Stu said try starting the engine with the raw water thru hull shut off.  I professed that in the Mainsheet - when you change out your injectors.  
In fact a good rule of thumb is to shut off that thru hull if you have to hit the starter for the 3rd time.  You have plenty of time after the engine starts before you can do any damage.  How much - I'll estimate about 5 minutes!!