Mercruiser Start Up/Marvel's Oil

[Tunnaman88]

bought 1986 v with a 2001 Mercruiser 4.3l... harmonic balancer broke,,, boat sat for 2 seasons.. was properly winterized I was told prior to sitting. I replaced balancer got her all back together... now I am ready for next step... Being a rookie , I tried to crank her over .. but nothing .. Starter sounded like it wanted to go , but engine didn't move. My Buddy told me I shouldn't of attempted ... that I should pull plugs and spray marvel's M Oil in each cylinder and let her sit for a week.. then take off belt.. pull plugs and then try to crank over maunually with a breaker bar to break free..... any thouhts... engine has less than 400 on her