Have some updates. I got a friend who is the Yamaha (the actual Yamaha Marine) engineer. He came and had a look at the motor. He also said that cylinder number two was rattling a little. He checked all cylinders with the compression meter and compression was fine. However, he recommended that if I wanted to keep the motor for this summer and because of the log trips I do I should open it and change what needed changing.
His charge very reasonable (not hundreds of Euros ... is a friend after all), and all service guaranteed by Yamaha.
I can use my own spares if I want to also he said.
So he took the block off and after close examination the motor needed 4 pistons with pins, bare rings etc (so I will buy the set of 3x2).
However, something else transpired.When I changed boats I wanted to keep this motor but had to put an extension to make it extra long. Which I ordered from the US and mounted it up. What happened the shaft (is about 15cms long) of this extension was found to be twisted by 10 degrees or so. Apparently it needs changing too and it was a good thing that the motor was opened as I may had a problem very shortly according to my mate.
Also the pipes where the salt water is passing through were more or less blocked although I wash the motor with fresh water every time I take it out of the water.And that is on every trip. So there you go, another little thing that needed attending.
Any way the repairs now instead of costing me 1500 Euros (is near to 1500 pounds by the way), it will be a little less than 1000 euros with spares including this shaft (if I can find it from the US). If any one can help me by giving me a site where I can buy it from I would appreciate it.
Will keep you updated and if I can take photos will do and post them here.