1981 galaxy 1978 merc inline 6cyl 250 with 165 merc outdrive , gave it a tune up the other day and it just dont have the power it had before tune up , was thinking maybe the plugs are were not gaped properly when i purchased them at advance auto, 20 years of experience as a mechanic he has under his belt led me to beleave when he told me that all plugs for that motor came pre gaped . what is the gap for the plugs ,i was told by another boat mechanic that it was .035 is this correct.thanks, george
