2hp Yamaha Outboard Dumb Question

[lockie]

I'm rebuilding my tender 2hp Yamaha outboard, and I have a new piston. It has the word "UP" printed on the crown, as well as an arrow.

Sounds good so far, but if I have "UP" reading the right way up, the arrow points down, but if I have the arrow pointing up, then "UP" is upside down.

Yeah, I know I'm dumb, but can someone please tell me which is the right way UP for the piston?

Cheers, Graeme

[Blue Stocking]

How is the original piston placed ? Does this relate to a locator pin in the ring groove to stop the ring gaps catching in an intake port. Have not had my 2hp Yamaha apart yet.

[model 10]

It's the arrow."Up" is the label for the arrow, not the side of the piston it's on.

[lockie]

Based on a bit of googling, youtubing and responses on another forum, it seems the arrow points (down) to the exhaust port, and "UP" goes right-way-up at the top. This keeps the ring ends away from the exhaust port.

The interesting thing is that the piston was the other way round when I stripped it down, which might explain the broken ring and piston that got me to this point. I bought this motor in close to new condition, and I believe it had not been stripped down at that point. So maybe this is one of Mr Yamaha's rare goofs.

Cheers, Graeme