1823 should have a cast fuel tank, a stepped flywheel, a timer lever with an aluminium button and an anticavitation plate that is separate from the gearcase. All these things should be different than your A25. Also check to see if the serial number on the block matches the rope sheave. You can email me the photos if you’d like. I can post them for you.
Wayne
Upper Canada Chapter
uccaomci.com