No water in exhaust!

[Txlawdog]

I have a 1985 Catalina 30, with a Universal M 25 which was just rebuilt. I installed the rebuilt engine yesterday and today I connected everything and started it. I noticed there was very little water coming out the exhaust, just a trickle! I could here it gurgling at the stern of the boat but there was very little discharge. The temp got up to 200 and I shut it down! Any thoughts as to what may be causing this? I am sure it is something simple, but I just can not see it. For reference, the engine was test run 4 plus hours with no over heating issues and had good discharge. I have been through the air lock / burping the cooling system procedures as well. Any suggestions would be appropriated.

 

[Stu Jackson]

There are only a few "parts" to the raw water system.

Pump: faceplate, impeller
Thru hull: clogged
Hoses
HX
Muffler
Exhaust hose

check 'em all, good luck

 

[duality]

strainer?

 

[rpell1@msn.com]

From experience.....the gasket between the exhaust riser and engine can be installed in reverse, causing a blockage. Since it was recently done, re-open to make sure it's in correct position. Otherwise, as Stu has already suggested, check the obvious first.

Good Luck and Happy Sailing....

I have a 1985 Catalina 30, with a Universal M 25 which was just rebuilt. I installed the rebuilt engine yesterday and today I connected everything and started it. I noticed there was very little water coming out the exhaust, just a trickle! I could here it gurgling at the stern of the boat but there was very little discharge. The temp got up to 200 and I shut it down! Any thoughts as to what may be causing this? I am sure it is something simple, but I just can not see it. For reference, the engine was test run 4 plus hours with no over heating issues and had good discharge. I have been through the air lock / burping the cooling system procedures as well. Any suggestions would be appropriated.

 

[Txlawdog]

Headed to the boat now. I think I may have killed the impeller and will check that first. Thanks to all for your suggestions.

 

[Stu Jackson]

From experience.....the gasket between the exhaust riser and engine can be installed in reverse, causing a blockage. Since it was recently done, re-open to make sure it's in correct position. Otherwise, as Stu has already suggested, check the obvious first.

Ralph, wouldn't that only block the coolant flow and not the raw water?

 

[rpell1@msn.com]

In my case, the reversed gasket blocked raw water causing a gradual increase in engine temp. The only reason I was able to discover it was from the lack of water in the exhaust.

Ralph, wouldn't that only block the coolant flow and not the raw water?

 

[Txlawdog]

I had a kink in hose from the heat exchanger to the wet exhaust mixing elbow. Swapped out for a new hose, but she is still running a little hot. I noticed the nipple on the mixing elbow seemed to be the wrong size, prob less than 1/4" diameter. It's a home made exhaust system from the PO. I am going to swap out for the correct Universal part, that shows the nipple being 5/8" diameter. That should increase the flow of the water through the system.

 

[Txlawdog]

This is the water injection nipple from the mixing elbow the PO made. I'd say this would cause the high temp. Specs call for a 5/8", this is less the. 1/4"! I am going to rebuild the entire exhaust system.

 

[Stu Jackson]

Good idea. Have you considered a new prefabricated exhaust riser from Catalina Direct? Their pricing is high, since they separated the costs of the metal and the insulation, and I've heard (man, I hate that phrase but I read it right here!) that they won't sell the metal without the insulation), but I don't know what your plumbing skills are.

Our C34 manuals have a good sketch of the exhaust systems, so I suppose the C30 manual would as well.

 

[nlneilson]

On my previous C27 the exhaust manifold had the water circuit completely blocked.
For a new one at approx. $500 I bought a bottle of muriatic acid, poured it in, when it stopped bubbling poured it out and repeated for several hours. Worked great.

Hook a water hose where the outlet of your pump is to find any blockage.
Be careful not to fill the muffler and the exhaust riser after the muffler or the water nay go back into the engine, not fun. Check flow out of the pump with the engine running, as mentioned in a previous post check the impeller, if the engine was run without water to the pump the rubber impeller can heat up and be ruined. The water strainer or a stuck thermostat could be your problem.