Flushing seawater cooling system

[Compass790]

Originally Posted by Windward mark

That's all very encouraging, all the work is being done on a mooring so a bit tedious at times.
From searching on line the hand crank appears to connect to the flywheel via a chain not unlike a bicycle.
Currently have the old anode soaking and hopefully will eventually get it out.
My list of replacement parts is growing and would appreciate the name of your supplier to keep costs under control

You will have to private message me as wont put supplier
info in public. My YSM8 doesnt have chain drive on hand crank, think that is probably the earlier YSB & YSE versions. If it doesnt have a sprocket on the handle base it wont be chain drive.
Hope that helps

[hugosalt]

Do some cold weather starting with my 31 y.o. 3 GM raw water cooled as I sail March thru Dec. here in New York on Long Island sound...and Jan. and Feb. on several friends boats.
As stated heated air in intake great, have used battery booster with inverter as no shore power available. Also have used my portable catalytic propane heater in engine compartment to heat up prior to starting.
Run motor 15-20 seconds with decompression levers off to circulate oil for better compression and for health of motor.
Start with 3/4 throttle then throttle down when she starts(Yanmar recommends for GM
series)
Very important, really need batteries to crank big time, I keep topped off with solar panel. Not always the case in cold weather.
Also, here in the states, refineries go to winter blend diesel in the fall, but most of us sailors have diesel from the summer in our tanks...I add as much as 20-25% keresone
to my diesel for cold weather as this is what the refineries are doing. Motor starts/runs
happy when cold. If hesitant to do, just ask your local gas station if they went to winter
blend deliveries yet and buy some.
If you decide to flush with Rydlyme heat up motor to operating temp to open thermastat, I always change my impeller afterwards...realize you have to install new now. Also thinking must neutralize rust after flush with baking powder bath. have to check notes or should be in Mainesails instructions.
Have been using above practices for 31 years since boat new, on average 9-10 months
a year with no major repair/replacement and usually running her hard.

[JD-MDR]

I 'm in So Cal so I don't have to worry about cold weather but I have had problems with my ysm12 mixing elbow. I thought the flush with Ridlym was sufficient but found out this year that I was only cleaning the water port. The exhaust side of the elbow had much buildup of carbon. I bought a new elbow and the volume of water coming out is much better. Now I get the full 3000 RPM's like its supposed to. My engine starts perfectly always. Do you have a problem with the compression release?

[RaymondR]

If internal rust is a problem there is a company in Perth called Liquid Engineering which makes a product called Coro Dip which eats rust and is pretty harmless to most other things. Dilutes 6 to 1 with water.

[Compass790]

Originally Posted by JD-MDR

I 'm in So Cal so I don't have to worry about cold weather but I have had problems with my ysm12 mixing elbow. I thought the flush with Ridlym was sufficient but found out this year that I was only cleaning the water port. The exhaust side of the elbow had much buildup of carbon. I bought a new elbow and the volume of water coming out is much better. Now I get the full 3000 RPM's like its supposed to. My engine starts perfectly always. Do you have a problem with the compression release?

Yea the carbon buildup is a real problem. In the workshop manual it says to run them at max revs briefly before shutting down. Also run at max revs 5 mins per hour running I read was advice from Yanmar. Who does that? Maybe we shud. I found carbon not too difficult to remove with an old screwdriver tho when you take elbow off for inspection.
Hope thats of some use

[svstrider]

Originally Posted by Windward mark

Impeller fins were ok but it looks like the cross piece in the centre was turning without the fins.

I have a Yanmar 3GM30 and found on two occasions over the past 2 years that two fairly new Yanmar brand salt water pump impellers failed in my two engines due to the ?spindle separating from the vanes.

I took it up with the Yanmar supplier and they said I must have run the pump with no water in the line, which I had not. Recently, I have had no further problems,so I think it was some sort of manufacturing fault with a batch of impellers.

On a matter related to flushing the cooling manifold on my 3GM30 raw water cooled engines (+2500 hrs), I see that I could easily run a line to the inlet on the top of the manifold as an entry point, thus bypassing the raw water pump. However, the exit from the manifold into the exhaust elbow is not by a hose but by a channel inside the block. In which case, how do I close the circuit on the exit side? OR do I remove the whole exhaust manifold and soak it in vinegar overnight or dilute HCL for 30 mins (?concentration).

[JD-MDR]

I also had to replace an impeller way too soon, the same problem, the center separating from the rubber part with the fins. The Yanmar rep said I just got a bad one. He said it happens some times. But this time I didn't forget to put a little grease, although I don't see what good that would do after many hours of service. I
As I put in my other reply. Flushing out the water ports doesn't do anything for the carbon buildup coming out of the engine. They told me there is no way to get that out and to just replace the mixing elbow. It didn't cost asd much as I expected.

[iyamwhatiyam]

I have a Catalina 30 with a Universal M25XP. It has its own coolant system and uses a raw water heat exchanger. Should I run the engine briefly before shutdown with the thru-hull closed to flush the raw water from the heat exchanger? I have seen this mentioned in one place, but not all I have come across. Hopefully I understood it correctly.

[Cheechako]

Originally Posted by iyamwhatiyam

I have a Catalina 30 with a Universal M25XP. It has its own coolant system and uses a raw water heat exchanger. Should I run the engine briefly before shutdown with the thru-hull closed to flush the raw water from the heat exchanger? I have seen this mentioned in one place, but not all I have come across. Hopefully I understood it correctly.

No, you wont flush it all out anyway and risk damaging the impellor.

[Boatyarddog]

Originally Posted by iyamwhatiyam

I have a Catalina 30 with a Universal M25XP. It has its own coolant system and uses a raw water heat exchanger. Should I run the engine briefly before shutdown with the thru-hull closed to flush the raw water from the heat exchanger? I have seen this mentioned in one place, but not all I have come across. Hopefully I understood it correctly.

Once your sea water pump reaches maximum suction the water flow stops with the seacock closed.
Install a inline tee plumbed for a garden hose into your raw water pick up between the ThruHull and strainer,and use the dock water to flush the salt water out of the entire raw water loop, by running the engine with enough fresh water to keep the strainer full, but no more.


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