lean fuel

I recently had my '97 pro V 200 blow a cylinder and did quite a bit of damage. Attempting to have it fixed but the mechanic said it was probably from lean fuel. does this mean it was not getting enough oil or was the fuel I was using too low in octane?? Don't want it to happen again.

[boats.net]

Lean fuel condition is probably from dirty carbs. Rebuilt carbs and fuel pumps. That engine uses 87 octane fuel.