Closed raw water valve

[fox islander]

Last week the wife and I took off on a 6 day cruise in Puget Sound. Before starting the motor I went thru the normal routine including opening the raw water valve. I tend to eyeball the temp gauge every few minuits or so...after maybe 3-4 mins of motoring I noticed the temp gauge was pegged at 240...I've never seen it abouve 160 before. I immeadiately shut down the motor then went and looked at the valve. It was closed. Obviously I failed to close it on the last outing, which resulted in me closing it prior to starting. I wasnt sure whether to let the motor cool down slowly or start it up and get some water going thru it...I chose the latter, resulting in a blast of steam out the exhust. The motor cooled down to 160 in about 2 mins. We continued on the cruise and the motor perfomed normally. First question is should I have ran water through it right away? And second, how much damage have I done?

-Steve
1990 C30 MkII w/ the M25XP

 

[Stu Jackson]

Been there, done that

M25 on a 1986 C34. Check the impeller, better yet replace it, and just keep going. Stuff happens, my excuse was exactly yours, and it does happen!

 

[Bob S]

Did the same thing last month

with my M25XP. I had opened it to motor/sail off the mooring and closed it once at sea. about four hours later I decided to start her to recharge the batteries and forgot I closed it until I saw the eng temp. Unfortunately I totally destroyed the impeller. So now I know how to change it. I have a spare onboard which I didn't before. Lots of good advice here. I don't bother closing the thru hull anymore while I'm aboard. I close it aat the end of the day and put my key on it so I don't forget.

 

[AXEL]

put a cork in it..

I always like to close the seacock when I'm under sail. I have made it a habit to stuff a small wine bottle cork in the key hole pressed up against the key when I close the seacock. I can not start the engine unless I remove the cork. This is to remind me that the valve is closed.

 

[Bob S]

Good Idea

I like to close all thru hulls when not in use. I like the cork idea, I will have to try that.

Do most people close the raw water intake when sailing only to open it when they start the engine?

 

[AXEL]

I had problems

I had a problem with my engine about 15 years ago when I bought the boat. The anti-siphon valve clogged and the engine would fill up with sea water. At first I thought it was an electrical problem because as I was cranking the engine actually sounded like it had a short but if fact was trying to blow out seawater. Once the problem was solved all has been well until this season it happened again (while sailing). I think the elbow is getting clogged. This time I had to take the exhast hose off to blow out the seawater and in the process a lot of black stuff as what looked like seaweed blew out of the elbow. In addition my just replaced seawater pump is leaking again which tells me I'm building up pressure in the exhast.

Anyway....I have made a habit of closing the seawater valve at least for this season while under sail. It's probably a good idea especially if your sailing off shore.

 

[Hermit Scott Catalina30]

temp

I would change the oil if you are not using synthetic. High temps break down regular oil. I am not a chemical engineer but best to not chance it.
I am thinking of installing a switch to the starter solonoid so I can't start the engine until the sea cock is open. I just rebuilt my engine and I keep running the assembly through my head wondering if I torqued all the bolts down.
I do the same thing with the sea cocks, wondering if I closed them, when I leave my boat. I think the switch would help me sleep better.

 

[fox islander]

Thanx for the help

I took your advice and replaced the impellor...no pieces missing but some of the vanes looked a bit warped. One benefit is there seems to be more water squiting out the exhuast. I think i'll stick with closing the valve after a sail.

Cheers -steve