raw water strainer

[Lummisailor]

We have put our R25 on a trailer for the first time yesterday and have a question about freshwater flushing the Yanmar. Our boat has a composting head so the sea water out let in the strainer outlet for the head is unused. Can I use that outlet to back feed fresh water into the strainer to flush the engine? And what is your opinion of adding saltaway as I flush.
Thanks Larry on Synergy

 

[knotflying]

Never "force" water into the engine. It can cause real problems with the potential of water backing up into the engine head and then down an open exhaust valve. Remove the cover, close the sea cock put a running hose securely in the strainer basin and then start the engine. Be sure the hose will not fall out of the strainer and cause the impeller to run dry.

As far as salt away use. I have mixed feelings on that. First, if I were to use it I would pour it in straight until it ran out the exhaust and then let it sit overnight and then flush the next day. I would do this if it were once per season. If I was doing it after every couple of uses then I would pour in a diluted version and be done with it.

If it were me. I would do a fresh water rinse when I could and keep track of my engine temperature. If I see I am starting to get higher temps and it is not due to raw water intake or other issues, I would do a Rydlyme treatment. I published a procedure to do that on Tugnuts. You need to remove the impeller to do the Rydlyme circulation so I would do it when I was doing an impeller inspection or replacement.

 

[Capt’nKarl]

I'm not sure if the R25 has the same cooling system set up as the R21 but here's what I do every time I take my boat out of the water. I have an in-line male garden hose connector mounted next to the sea water strainer which makes it easy to access the cooling system. I purchased a 5 gallon bucket from Home Depot along with an installation kit with a male adapter that makes it easy to attach a garden hose to the bucket. I have a 15 ft section of garden hose with female connections on each end. Attach one end of the hose to the bucket and fill with water. When the water flushes out the other end of the hose attach this to the male garden hose connector on the cooling system. Close the raw water intake valve and start the engine. Keep adding water in the bucket as the engine starts to flush. I let the engine run at idle for a few minutes then slowly increase the RPM's making sure the water in the bucket keeps up with the outflow from the engine. After you've given the system a good fresh water rinse just detach the hoses and close the system. It works great. You don't have to worry about over pressurizing the cooling system this way.
Maybe this would work on your engine system.

Cheers!

Karl

 

[Lummisailor]

Thanks Carl
I have used the system you refer to on my last boat which was a Transpac 32 I put a tee in the the hose from the sea cock with a ball valve and closing the sea cock ran fresh water and a mixture of saltaway from a barrel . It seems like I could use the spare port on the strainer which previously fed the head.But I will talk to the factory about this idea.
Pura Vida Larry on Synergy

 

[Lummisailor]

OK I give up on my flushing idea. Why reinvent the wheel. Will run water into open sea water strainer. Thanks for the comments.

 

[Stevan47]

Hi Capt'n Karl: I liked your idea re flushing the engine of your R21, however I do have a query. I still flush my sea water system after every trip when I get home by connecting a garden hose to the sea water suction line, f'rd of the strainer. I usually give it three to five minutes and also check to make sure water is coming out of the sea water suction port in the hull. My R21 lives on a trailer in my driveway when not underway. I am concerned about the vibration effect on the trailer, engine mounts, boat fittings, etc when running the engine out of the water. What are your thoughts on this? Kind regards, Stevan