Amazing; the little engine that does!

[David W]

We have a circa 1978 raw-water cooled Yanmar 2QM15 in our Crown 34. Coming back from our last trip I noticed the water flow from the exhaust was a bit less than usual.

Today, I pulled the water pump and changed the impeller. There was nothing wrong with it but since it has never been changed in the 6 years we have owned the boat (I know, I know...) I figured it was time.

I also checked the engine zincs. I did replace these when we bought the boat (do I get a redeeming point for that?) but not since. Today, they looked nearly new. I peered into the hole and it was amazingly clean. I've seen more scale on some faucets.

The cause of the reduced flow? A small wood chip had lodged itself in the 1/2" pump intake reducing the opening by about 25%. Pulled it out and put everything back together and presto, mega water out of the exhaust!

I might look at a raw water strainer to avoid this in the future. After all, changing impellers every six years is a maintenance nightmare

Boat maintenance angels; keep shining on s/v CinDino!

Cheers,
David

 

[tomgrigsby]

My 79 Hunter 30 doesn't have a raw water strainer either. I have contemplated installing one, but haven't got there yet. The little Yanmar 3GM is sure happy as is. Not sure what might get in there, but changing the impeller is probably a pain.

 

[Ed Schenck]

Never heard of that, seawater directly into the pump without a strainer? Lot of luck involved with that considering all the crap that is in the water. I am always finding bits of seaweed and little critters. I wonder what kind of clamshell you both have on the inlet thru-hull, maybe kind of a strainer there. And Tom, you really have a 3GM in your H30?

 

[Ross]

I have been amazed at what i haven't found in the raw water strainer. We have come very near grounding several times and stirred up a lot of mud on our way through. I always check the strainer the next time it is reasonable to do so and the water within a foot of the surface must not have much trash in it when you draw 4.5 feet even if a foot of that is soft mud. I am sure that there have been times when we were cultivating and not navigating.

 

[zeehag]

when i bought nmy ericson there wasnt a strainer on the raw water intake for my yannie either-i have a 2 qm 20 h. i love it. is awesome. never heats up much less overheats. is impressive. besides the water strainer element, i have a strainer on my thru hull fitting outside the hull. so far i have found no weird stuff in my strainer element.

 

[Freedom77]

Yanmar is the Volkswagen of boat engines. Just like the bunny they just keep going and going. Fair Winds, Old Salt...

 

[Benny]

Actually most of the older Cherubinis that were raw water cooled did not come with a strainer as factory equipment. I guess it depends on how far below the waterline is the raw water intake located as crap in the water usually floats. I find the newer Hunters with the raw water intake farther astern do require the use of a strainer. Among the strangest things that we have ingested into the raw water strainer was a jellyfish. Talk about a gouey mess. We clean our strainer regurlarly together with the one for the A/C and usually find sea grass and pieces of floatsam.

 

[ChuckThomas]

just a thought about zincs. ours looked like new but was hollow. cracked it like an egg with hardly any pressure from a pair of pliars.

 

[David W]

Zincs were solid

just a thought about zincs. ours looked like new but was hollow. cracked it like an egg with hardly any pressure from a pair of pliars.

Yeah I wonder too but they were solid as, well zincs when I scraped off the bit of scale that had accumulated.