1972 johnson 20 HP Growling noise

[johnson72]

Hi. My 72' Johnson 20 hp sounds a little funny when accellerating or slowing. There is one range of rpms that sounds much different than the rest. It is hard to explain, but it is almost like a high pitched growling noise. My motor accelerates a little slow for a 14 foot starcraft aluminum, but it does have the biggest prop recommended. I read somewhere that the growling noise might be bearings? I don't think it is serious, but if it will hurt my motor i will defenitely fix it.

Thanks everyone!