Coutts, Rattle sound? Did this happen gradually or did it just happen all-at-once? Maybe something loosened up or the muffler mounting bracket is cracked/broken. A peek inside with the covers removed is needed.
Also, it could be combustion chamber pinging you are hearing, caused by heavy carbon deposits in the combustion chamber, which will raise the compression ratio to a higher value that causes it to ping on regular grade gasoline. If so, liquid chemical de-carbonization (or engine disassembly) is required.
thank CycleRob for your reply
the generator in question is new out of the box. I have taken it back to the shop and they suggested that the noise was coming from the generator coil and that this is normal.??? I must say the shop was a Honda dealership as this was the only one in town.
if this is normal it is a bit disappointing as the noise is noticeable when running but not a deal breaker. it just means that the motor is quitter than the coil.