Yamaha Outboard Cooling Problem

RoyS

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Jun 3, 2012
1,742
Hunter 33 Steamboat Wharf, Hull, MA
I have a 2-1/2 HP Yamaha four cycle outboard on my inflatable. Every year a build up of something that resembles tooth paste develops under the plate that the impeller sits on. The engine operates in salt water and I only flush it with fresh water at the end of the season. During the winter I open it up and manually remove the "toothpaste". Eventually the cooling flow would completely stop if I did not manually clean it out. It is just about blocked by the end of the season. Does anyone know of an additive that might dissolve this build up during the post season fresh water flush?
 
Feb 17, 2006
5,274
Lancer 27PS MCB Camp Pendleton KF6BL
Flush after each use when in salt water (I know, had the same issue with lack of cooling water flow). Use Salt Away mixed with fresh water. I believe it comes in a contain that can be attached to your hose.

My older Yamaha did not have a flush valve, so I made an adapter to put on the pee hole tube to back flush. Took a little time to find the right hose fittings, but the end result cleaned out the gunk.

Don't just use fresh water because that also contains hard elements that will clog your cooling path. Use Salt Away.
 
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Likes: dLj

RoyS

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Jun 3, 2012
1,742
Hunter 33 Steamboat Wharf, Hull, MA
Thank you, Brian. I was afraid that suggestion might be the answer. It is totally impractical for me to flush after every use. What were the designers thinking when they made this thing? Should have had a label that said "Fresh Water Only." It would be easier for me to just row without the engine. Does anyone make a small salt water outboard?
 

dmax

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Jul 29, 2018
1,163
Telstar 28 Buzzards Bay
I also have a Honda 2.3, nice to not have to worry about salt - my previous Nissan 3.5 clogged up to the point that no water came out (ran hot but still ran).
 
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Likes: Timm R Oday25
Mar 2, 2019
570
Oday 25 Milwaukee
Well Roy ,it appears you have your answer. All is not lost , I'd be willing to help you offset the cost of the replacement motor .
We sail in Lake Michigan and I'd be more than willing to make you an offer for your Yamaha !