I am UK based and have a 312 Y Block in a 54 mercury

When you first start it up on tick over the engine has a loudish knocking noise

When revving and running the engine it sounds sweet and has no problems

Is this tick over sound a normal sound or something sinister - I know its hard to say without hearing but would appreciate any feedback (I have no other y blocks in my area to compare it to)

Thanks in advance

Jaz