Backwards piston?

I just became aware that pistons could be installed backwards. My engine came disassembled, so I want to make sure I didn't put the piston on backwards.

There is a "3" etched on the top of the piston. It currently is on the same side as the air intake. The ring openings are both more towards the exhaust side than the intake side.

Do I need to flip it before the first run?

Southgate Jonny said:

The pins that keep the rings in place should be on the intake side.

Click to expand...

Darn. Thanks.

Unfortunately I had already oiled it. made a mess. But oh well, I have an engine now.