Engine overheating

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beached79

Coming back to the dock the other day, I noticed the engine wasn't pumping any water overboard and the engine was overheated. I was thinking either the strainer was clogged up or the raw water impeller needed to be replaced. I can't get the cap on the strainer off..does this sound like a good diagnosis? Anybody have any suggestions about getting the strainer off, possibly a strap filter wrench? Is there another possible issue?
 
Feb 26, 2004
23,049
Catalina 34 224 Maple Bay, BC, Canada
Telling us what engine you have would be a BIG help.

If it's an M25 or derivative thereof, take your heat exchanger off, check the zinc and fallout from an old zinc, see if you need to clean out the HX fi there's gunk inside, and then check the HX ports where the hoses from the raw water pump to the HX connect; it tends to get gunked up with salt fallout. Check your raw water impeller, too. If you don't have a freshwater cooled engine, I dunno. That's why it's important to give us some information with your question.

See this: http://forums.catalina.sailboatowners.com/showthread.php?t=101369
 
B

beached79

m25

It is an M25, I replaced the fresh water pump and a few hoses last summer. The heat exchanger needs to be pulled out and boiled out and the zinc replaced (it's on my agenda). I thought I'd start with the raw water impeller, strainer issue and work from there. Getting the heat exchanger out and new hoses isn't a bad idea.
 

JIM B

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Jun 27, 2006
107
Catalina 30 MKII ROOSEVELT AZ
Might as well start at the beginning

Instead of looking for the problem starting in the middle - make sure the through hull is open and not clogged. Working your way back to the strainer, heat exchanger, etc...

This time of year we get a lot of runoff. Often there is a lot of junk floating on the surface that can clog the freshwater intake. I keep a dinghy pump handy to blow out the through hull from the inside.

Good luck
 
Feb 26, 2004
23,049
Catalina 34 224 Maple Bay, BC, Canada
To clear out the thru hull

take the hose off the rw pump, open the thru hull and blow thru the hose with a dinghy foot pump! Sometimes the rw strainers don't leave enough room to do that at the thru hull.
 
B

beached79

update on overheating

all right, here's an update..i put a new impeller in the water pump, cleaned out the strainer, cleaned out the hoses and there's still no water being put overboard..maybe the pump has to be primed somehow. i went ahead an yanked out the heat exchanger, taking it to be boiled out tomorrow (it was pretty gunked up), i don't think that would cause a loss of suction. the impeller needed to be changed and there was trash in a few of the lines, i'm thinking you have to prime the pump somehow to get the air out of the system...any ideas from someone whose done it before?
 
Feb 26, 2004
23,049
Catalina 34 224 Maple Bay, BC, Canada
M25 engine overheating

...i put a new impeller in the water pump, cleaned out the strainer, cleaned out the hoses and there's still no water being put overboard..maybe the pump has to be primed somehow. . yanked out the heat exchanger, taking it to be boiled out tomorrow (it was pretty gunked up), i don't think that would cause a loss of suction. the impeller needed to be changed and there was trash in a few of the lines, i'm thinking you have to prime the pump somehow to get the air out of the system...any ideas from someone whose done it before?
I'm somewhat unclear. Cleaned out the hoses and trash in a few of the lines? How old are the hoses? OK, given the $ involved, you may have had to leave the old ones, but how can you be sure they're fully clear, some of them are very long.

The rw pump is an impeller pump (see: http://www.westmarine.com/webapp/wcs/stores/servlet/westadvisor/10001/-1/10001/PumpTypes.htm). On your engines they are usually below the waterline, so once the thru hull is open, they don't need to be primed.

You need to carefully check each and every step of the system and assure they are clear. Step-by-step. Also, check the angle barbs on the rw pump - if you got stuff in the hoses, it could gum up the elbows.

If you have a hw heater, read this, BURP, on the freshwater side http://c34.org/bbs/index.php/topic,4518.0.html

If you'd like more info on your engine, try wandering around our C34 website, lotsa engine info there: www.34.org and our new wiki: http://www.c34.org/wiki/index.php?title=Main_Page
 
B

beached79

strainer

the hoses are in good shape, and clear to the heat exchanger..i took each one off and blew them out. the strainer is mounted above sea level and then flows back down to the pump, i'm going to check out the fittings on the rw pump (the only thing i didn't pull out and look at). the heat exchanger needed some tlc anyway, so i'm taking care of that tomorrow. i've got a new problem now, when i was putting the new impeller in, the shaft was pulled out halfway. i put it back in, but now there's a small leak coming from the pump itself.
 
B

beached79

impeller rubber

thanks for the help guys..i opened everything back up today, put the hx back in and connected it together (new hoses), the output side of rw pump was full of old impeller parts. cleared it all out, primed the pump, started the boat and it ran great..cooler than ever before. thanks for the help. happy sailing, cheers
 
Nov 28, 2008
35
Catalina 30 Northport, NY
Please make sure you have accounted for ALL the impeller parts as they can become lodged in the worst places.
 
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