pinging noise in lower unit

[Claude Moreau]

I have a used 1987 Mercury 70 HP outboard with a noise coming out of my gearcase. I just tried it out and at times heard a loud rattling noise, like pinging from engine knock. The first time occured after I had slowed down and then speeded back up. Later it went away after restarting the motor. Later, while operating only on my other (Portside) engine, the noise reoccured, while off, and in neutral, as the prop was being turned by the water flow due to foreward motion of the boat. After restarting the motor the noise went away. What could be causing this noise and how can it be fixed?

 

[mellowyellow]

Re: pinging noise in lower unit

drain lower unit oil and inspect for signs of<br />water intrusion and for metal filings on mag.<br />drain plug. post back results.

 

[roscoe]

Re: pinging noise in lower unit

After doing the above, adjust the shiftshaft linkage so that it fully engages in F and R, and dis-engages in Neutral.