Deck caps and petcocks (oh my)

[Kevin Henderson]

Did a nice shakedown cruise of Pau Hana today.  Pretty dicey weather for us weather wimps in San Diego... we actually had rain and storms 
Trying to be the conscientious and mindful boat owner I thought I would check out the Aqualift petcock prior to cranking the engine... (just in case)... The wingnut on the petcock was completely corroded and with the smallest pressure.... broke off and is unusable for certain.     No leakage and I started the engine just the same and had no problems whatsoever.
Afterwards (also trying to be a mindful boat owner) I pulled up to a dump station and went to remove my waste deck cap fitting.  It was solidly stuck in place and brittle and when I used a wrench handle to it...... you can guess the rest.     After digging all the pieces away from the deck fitting and successfully pumping the tank... I relegated a rag to do the job of the deck cap.
I have just finished ordering the replacement deck cap fitting for the waste cap from Catalina Direct.  I also have ordered the replacement petcock valve assembly for the Aqualift muffler...
Now the big question..
How big of a job is it to completely replace the petcock valve on the muffler?  Should I get a mechanic to help or is it a straightforward DIY job?
Also... what else should I be doing and am I screwing things up?   

[Ken Juul]

The petcock should just unscrew from the muffler.  Remember the muffler is partially filled with a black nasty water/exhaust mixture.  So either old out, new in very quickly trying to minimize spillage or take you time and let it drain then clean the mess out of the bilge.

[Stu Jackson]

Turn your engine over a few times with the stop handle pulled up, less than a total of 30 seconds, just like it says on the cockpit control panel.  It'll push some of the yucky water out of the muffler.  Ken's right, it's an easy screw in job.

[Ron Hill]

Kevin : That petcock is a standard 1/4" pipe thread.  Get a new one at an auto supply store.

As for changing it, here's what I'd do :  Start the engine, go below and shut off the raw water thru hull, then go back up and shut off the engine.  You should have minimal water in the muffler.  Back out the old petcock and install the new one - work fast!  A few thoughts

[Susan Ray]

I'm wondering how many of us check the petcock valve...ever? Mine was also rusted solid and wouldn't turn. I called a mechanic friend who came over and took out the fitting and put a bolt in it's place. If I ever get the urge to to check the muffler I will call him back!
I know this doesn't help anyone but it's what I did a year ago and I haven't worried about it since. (I think that petcock was at least 20 years old....) Aloha, Susan

[Ted Pounds]

Susan,
You should have your friend put a petcock back in.  If you ever have a hard time starting your engine and crank it for 30 seconds without it starting then you'll need to drain the muffler.  Otherwise water could flow back into the engine...  Just a thought...

[Ken Juul]

I think it would be just as easy to remove the bolt, plus no worries of petcock maintenance.

[Stu Jackson]

It sounds as if my petcock is locked in.  When I turn it out, the whole "bolt" cvomes with it, leaving the big hole.  So, I have two choices:  1) leave it that way;  2)  take it out and check the petcock in the bolt to see if I can loosen it.

Either way, it makes a hole in the muffler to drain water.  I don't see much of a difference.

[Kevin Henderson]

Thanks for all the  advice everyone.  I am waiting to get the new petcock assembly and replace it soon. 
I have a feeling once I "dig" into the old petcock, I will discover it will be better to replace the entire assembly (Petcock and fitting)  Got my curiosity up now to see extactly how difficult this turns out to be..... I'm hoping for no drama :-)

[Kevin Henderson]

Firstly, I would like to thank everyone with their replies and advice on this seemingly overly simple task of replacing the muffler petcock valve.  I ordered this valve from Catalina direct:

http://www.catalinadirect.com/index.cfm?fuseaction=product.display&product_ID=1932&ParentCat=71

I ordered this one simply because I wanted to ensure (remember I'm a newbie here   ) that I had an exact fit with no questions asked.  I was impressed by the brass fitting I received and looked forward to performing the replacement.  Rather than closing seacocks or cranking the engine with the stop handle pulled, I simply let the engine rest for a week.  I gathered several rags and sponges.  Since I had little room to work with and no idea how messy or how much water I could expect to see, I placed a bucket nearby and used an open soda can to catch water when I backed out the old valve.  To my astonishment the old valve spun out quite easily.  I noticed it had Teflon pipe tape on the threads so I was happy I had planned to do the same with the new petcock.  As I spun it out I was surprised to see clear water coming out of the opening.  Playing "little Dutch boy to stop the draining and using my trusty soda can I dispensed approximately 48 ounces of clear water from the muffler.  Spun some tape on the the threads of the new calve and spun her in and tightened up.  Shiny new petcock valve in place and ready to be used if the occasion ever arises.   
I might actually gt the hang of this sailboat maintenance thing :-)

[Ron Hill]

Guys : If you ever have a hard time starting the engine and have to try cranking for the third time here's a procedure to follow. 
I have recommended that after you change the injectors to do the same thing.  Turn the raw water thru hull OFF.  Crank the engine until it starts (don't keep the starter engaged for more than 15/20 seconds at a time or you'll burn it up).  After the engine starts you have more than enough time to go down the companion way stairs and open the thru hull.  The impeller can run dry for a short period and the muffler won't melt in that short period of time! 
Just make sure that the water starts spitting out of the exhaust.  A thought

[Roger Blake]

I'm with Ron...one year, during spring commissioning, I couldn't get the ol' iron going...was concerned about the aqualift flooding after so much cranking. So, shut off the engine intake until I got the ol' gal running, then ran down to open the thru hule.

[rmbrown]

I removed my petcock yesterday and was surprised that I got a little clear water but no gush and no great volume.  I didn't measure since it was clear, just let it run, but it was such a small stream that I am concerned.  I'd just run the engine for an hour or more.  Ideas, anyone?

[mark_53]

I removed my petcock yesterday and was surprised that I got a little clear water but no gush and no great volume.  I didn't measure since it was clear, just let it run, but it was such a small stream that I am concerned.  I'd just run the engine for an hour or more.  Ideas, anyone?

Instead of reviving 7 year old thread, you should just post a new thread so everyone doesn't have to read thru an old problem to get to your question. 
Did you open the fill cap first?

[Stu Jackson]

I removed my petcock yesterday and was surprised that I got a little clear water but no gush and no great volume.  I didn't measure since it was clear, just let it run, but it was such a small stream that I am concerned.  I'd just run the engine for an hour or more.  Ideas, anyone?

The output of the muffler is in glugs and spurts, i.e., uneven.  While the rw pump is constant at any given engine rpm, the back pressure of the exhaust gas is what pushes the hot water and gases out of the muffler.

You may just have shut down the engine right after a big spurt. Maybe it was a splurt!