Flushing raw water system

[PeterBld]

My son has just flushed the raw water system. The engine is a marine Ford 2712. He removed the impeller and used ordinary phosphoric acid diluted to an 8% solution, and with a diaphragm pump circulated the solution for an hour. The result was amazing. The insides of the bronze heat exchanger was shiny metal like new.
Does anyone else use this method?
We have a Perkins 4-236.

Pete

 

[jssailem]

Pete
Interested in your experience with this issue. I have a Perkins 4107 and have been wondering about engine flushing as a way of maintaining the engine coolant system. I see nothing in the manual.

 

[firehoser75]

Fresh water flushing of the raw water cooling side of your engine is a great idea, and if done regularly will reduce the need for full servicing of the heat exchanger. and salt water side of the cooling system. "Marine age" not how old your engine is, is the determining factor of most engine cooling problems (and the corrosion of affected parts). There is interesting info available on sbm.com under "Tony's tips". It is directed at power boaters, but it still applies to small diesels as well.
For the winter, I flush my engine with "Salt Away" and leave the product in the cooling system all winter. I do keep my boat warm with a small heater, and live where lowest temps rarely go below much below freezing.
Regards,
Tom

 

[PeterBld]

I tried “saltaway “ on an old outboard hoping it would remove old salt build up. It did not appear to improve the water flow so eventually I removed the head and found the salt still there, apparently unAffected by the saltaway.
I believe saltaway works well if used from a clean beginning to prevent salt build up. But cannot tackle old encrusted build up.

 

[Ron20324]

...I believe saltaway works well if used from a clean beginning to prevent salt build up. But cannot tackle old encrusted build up.

+1. Peter, that's about the same as vinegar in the toilet plumbing.

 

[firehoser75]

Not saying salt away will always work, especially for "long term" build up of salt and other particles (that requires "boiling" at the radiator shop), but if the heat exchanger has salt away in it all winter it does help. I usually flush it through 2-3 times (leaving it in at least 24 hours each time) then the last time just leave it until spring. The best way to reduce the need for more severe servicing is regular fresh water flushing and if possible after each use.

 

[All U Get]

I just did ours with CLR, let it sit in the warm engine for six hours. Seems like better water flow.

All U Get