IF ITS SELF PROPELLED CHECK THE DISC BEARING THATS THE PULLY DISC THAT MOUNTS TO THE DECK , WHEN THAT BABY GOES IT SOUNDS REALLY LOUD.

Does the noise sound like the exhaust? If so those older smaller engines did not have much of a muffler so the exhaust has quite a sharp loud tone under the best conditions.

No it is not self propelled.

It does sound like either exhaust or just a loud engine. There is no grinding or other odd sound. I did put a new muffler on it. Do you think that is just how it is supposed to sound?

Thanks for the replies!

Yes that is the likely cause.

You might also make sure it isn't over-speeding. I had one that the governor was set wrong on and it was extremely loud.