This may be a dumb answer...I could be wrong as all get out. But I wanna say my Johnny 15 had the model number on the "freeze plugs" in the block. Please feel free to tell me I'm wrong or mistaken or must have hit my head harder than I thought yesterday. It maybe have been model specific or just... well anyhow I believe I noticed it when I stuffed me 15hp on a 10hp rated hull and put 9.9 cover on and me friend pointed out that a smart officer could identify it as 15 even with ID plate missing due to freeze plugs.
If I'm wrong I hope it didn't take you and inordinate amount of time to look.
Sean
Ps
I'm fairly everyone else's advice should be taken before mine.
