Mercury 40 hp classic clanking noise

[Gbrown062]

I got this motor running and it makes like clanking noises but i cant tell where its from. Its got spark on all 4 cyl. Also no visible damage to piston heads, 125 psi on 3 and 115 psi on 1 cyl. Noise is there whether in gear or not. I have a video of the sound but cant post it here. Any ideas before i tear it all open?

 

[scrapper042000]

take a piece of hollow tubing or fuel line or vacuum hose and use it like a stethoscope to help isolate where the noise is coming from and go from there ,and as always do not rev this motor up ,when not in the water under load (they will make noise then and or blow the crank right out of it ,and you probably already knew that

 

[Gbrown062]

Yes i know that. Im just stumped with what it could be. Im not getting play in the pistons so pins must be ok and i dont think a bearing would soulnd this way.

 

[racerone]

Flex plate on the flywheel ??-----Drain gear oil and have a look for metal bits.