360 marine cranks?

School me on 360 marine cranks. Pretty sure the dart sport I bought came with 2 of them being as they both have repaired water jackets and the rebuilt one will not fire at all. Yes I have spark fuel and air. I've swapped and done this countless times this one will not fire one bit changed everything that could be wrong besides crank pistons and rods. Any way to tell externally?

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Author: admin