merc 115hp tapping noise

[danny9696]

I just put an old 72 mercury 115hp L6 on and 87 bayliner because the engine that was on the boat had a blown cylinder (1987 fource 125hp) but the engine has a tapping noise, should I be worried about it and take the power head apart and check the bearings befor running it any more. I cant tell were its coming from, is there something common on these, this is only my second boat and my first was a 200hp merc that was a blast. I have a fully equiped shop and was planning on getting into this engine but I thought I would ask around first. I do all my testing at my shop with a test tank so I can get right on the engine while it is running. seems strong I have not ran it for more than a few seconds at a time because of the noise.

Thank you for your time and advice

 

[Laddies]

Re: merc 115hp tapping noise

That sounds like piston slap and could be either a bad piston or worn cyl. Be prepared for the cost of a re bore if you tear it down, at that age shes probably got many hours on her.