1970 Mercury 1150 Noise

[Keith & Tonya Sheets]

There is a "clanking " noise when the motor is running. It is most noticeable at idle and every now and then it will stop making the noise and the engine purrs like it is supposed to. As the RPM gets high the noise seems to fade a bit. As far as i can tell it does not affect the performance of the motor. It idles good, runs out very nice, plenty of power. It seems to be coming from the lower part of motor, possibly beneath it. The motor does not shake when running, it goes through throttle range pretty smoothly. Any idea what may be causing this noise?

 

[Chris1956]

Check the pully cover on the distributor. A bit of blue locktiteon the bolt will stop the noise.

 

[Canufixit2]

Since you say it sounds lower end I'd check the lower unit for fluid level, water in oil and metal filings in the oil.

 

[Keith & Tonya Sheets]

Update on this...it turned out to be the flywheel. The center hub was broke. Replaced flywheel, purrs like a kitten again.