Yamaha Outboard Model Number

[TreeFrog]

I just purchased a used 2-stroke Yamaha Outboard and I am trying to determine the engine size and year in order to purhase some parts from Boats.net. It has no labels, decals, serial numbers etc. The previous owner told me it was a 30hp but I am not sure. Is there anyway to figure this out easy by searching an engine part number? Thanks.

[boats.net]

The model and serial number should be on side transom bracket, if not there is no way of identifying, might take it to a dealer to see if they help.