87 Merc 350 loud knock after 2mo. idle

[invader1]

After 2 months of dead battery, Installed new battery and I hear a loud repeating knock at the 2nd cylinder back on right.<br />Need ideas, comments for trouble shooting

 

[DJ]

Re: 87 Merc 350 loud knock after 2mo. idle

invader1,<br /><br />It could be just carbon build up. Get some "Top Engine Cleaner" from a GM dealer and give it a try. It won't hurt.