Yamaha 2HP Cooling Water "Blockage"

[gadgetman]

I've had a few of these in bits and the water passages are easy to clean with the power head taken off the mid housing and pulling the head off is " normally" straight forwards. Don't split the lower ( crank) housing unless you know what you are doing. There also isn't any need to do this for the cooling issue as there are no internal passages in that part of the engine. Also check the pick up tube for corrosion / holes. I've had one that was eaten through, so when the water pump pushed the water up it, some of it leaked out before it got to the power head. BHG Marine are a good source of Yamaha spares. I would recomend replacement of the gaskets every time as they are. It that expensive.
Good luck

 

[steve66]

Thats really interesting Gadgetman, your motors must have been badly corroded as all of the 2 hp yamahas i have serviced have had a copper pick up pipe.I have repaired many with blocks that have corroded away due to salt but never seen a pick up pipe corroded

 

[gadgetman]

It was either brass or copper, I had to sleeve it to fix the corrosion!

 

[kyleview]

Problem now resolved - never seen so much water being vented out !!!

Thanks everyone for all the input / assistance - much appreciated.

Would appear that cleaning the waterways where the shaft meets the engine, also around the head, improved things but did not resolve the problem. Eventually took the lower part of the shaft apart and checked the impeller which was ok, as I had expected. However the "water feed" pipe up the shaft appeared not to seated into it's rubber mount next to the impeller as had all sort of dirt attached to it's outer side - not corrosion. Just cleaned off with a bit of sandpaper, a smear of grease, and the refitted very carefully to make sure the pipe was correctly located as I engaged the shaft. Bolted up, started the engine, and LOTS of water out of the exhaust. I think when the impeller was replaced (professionally) in 2009 the pipe was not correctly located and hence minimal / no flow of water to the head. Does not really answer in my mind why I got some / not a lot of flow for first few minutes, but then tailed off.

Thanks all again - have saved myself money, also learned a LOT about the engine which I want to keep for many more years as it's light and easy to handle, also so reliable.

 

[steve66]

Glad to hear you have beat it. I agree these are cracking little engines and will last as long as you dont run them less than 50/1 and keep them well flushed with fresh water.
Well done, be careful though repairing outboards does become addictive!!!