Catalina 30 exhaust flow

Aug 12, 2012
12
Catalina 30 MKII Pensacola
My Cat 30 has an engine exhaust flow that is not consistent. I see regular jets of water with relatively low flow between. Is this typical? Should I be looking for issues?
 
Feb 21, 2013
4,638
Hunter 46 Point Richmond, CA
Typical. I would be concerned if there was NO water flow out the exhaust. Watch your engine temperature. Inpect your strainer for pluggage and clean. If it starts to overheat replace your raw water pump impeller then if it continues clean the heat exchanger.
 
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Sep 25, 2008
7,480
Alden 50 Sarasota, Florida
It would help knowing what engine you have in it. Some, like the 5411, only spit water which is the normal condition.
 
May 17, 2004
5,723
Beneteau Oceanis 37 Havre de Grace
It is typical for the flow to be irregular, not a constant stream like a garden hose. Water tends to build up in the water lift muffler before enough exhaust pressure builds to blow it all out, then the cycle repeats. As RPMs increase the pulses should get stronger and more frequent. I agree with Sail SFBay to keep an eye on it, and I’d inspect your raw water impeller just as a good maintenance practice. If it’s missing any vanes that will make the pulses more infrequent.
 
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Ward H

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Nov 7, 2011
3,792
Catalina 30 Mk II Cedar Creek, Bayville NJ
Chris, Your 89 MKII most likely has the Universal M25XP diesel, same as my 93.
@Davidasailor26 explained it well. That's how mine works and it's by design.
When you start your engine always check for exhaust water flow. The exhaust should start burping water in about 15 to 30 seconds.
If it doesn't, check that you opened the engine cooling water intake valve and if it is, check the cooling water strainer.

As David says, learn to check your raw water pump impeller as part of your engine maintenance procedures.
 

RoyS

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Jun 3, 2012
1,742
Hunter 33 Steamboat Wharf, Hull, MA
If your idle speed is too low water will build up in your water lift muffler and blow out in spurts as you described. Suggest that you check your engine idle speed.
 

dmax

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Jul 29, 2018
1,221
Telstar 28 Buzzards Bay
As everyone has said, typical. If you rev up the engine, you should see a big increase in the flow - mine will sometimes shoot water 30 feet when I goose it.
 
Jan 7, 2011
5,695
Oday 322 East Chicago, IN
Yep…irregular is normal. But when did you last inspect your impeller? A little proactive maintenance can save a lot of work later ( like if you let the impeller go too long and the little vanes break off and make their way into various parts of your cooling system…and you have to start tearing things apart to find them.
Greg
 
Feb 26, 2004
23,078
Catalina 34 224 Maple Bay, BC, Canada
You might want to investigate more and learn how a boat muffler works. Good luck.
 
Aug 12, 2012
12
Catalina 30 MKII Pensacola
Thanks for all the replies. This is my first diesel and I asked the question based on stuff I’ve read.

Engine temp is good, RW strainer is clean. RW pump impeller is new.
 

Tom J

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Sep 30, 2008
2,325
Catalina 310 Quincy, MA
Thanks for all the replies. This is my first diesel and I asked the question based on stuff I’ve read.

Engine temp is good, RW strainer is clean. RW pump impeller is new.
Questions are good! Welcome aboard, and please keep bringing up anything you have a question about. We have all been there and done that, and like to share our experiences.