Timing Chain/Belt Replacement When? Merc 120

[redgoat]

Does my Mercruiser 120 hp 153 cu. in. 4 cyl have a timing chain or belt? Or is it direct gear driven? Is this something that I should consider replacing since my Sea Ray is 43 years old? Cars routinely replace chains and belts at certain intervals but what about boats? Also, if my belt or chain breaks do I have an interference or non-interference type set up?

 

[JustJason]

Re: Timing Chain/Belt Replacement When? Merc 120

They use gears and should be good for the life of the block as long as they stay well oiled. The engine is non interference.