2006 175hp vmax 200 hours

Motor runs great, great rpms, starts right up, never had an issue.

Month ago starting hearing a rattling when I put it in gear. No noise when in idle. Motor runs great. Noise isnt loud, barely can hear it.

Any thoughts? I read it may be prop chatter?

Have you ever pulled the prop and checked for fishing ling wrapped around the shaft? Line wrapped will eat up the lower unit seals.

That needs to be checked from time to time.... Cheaper to remove the line than replace the lower unit seals.

I have not. Is it fairly simple to do? Can I do that without re-greasing?

It is easy. Get you a six point socket that will fit the nut. A 2x4 wooden block to hold the prop. The hardest part is getting the cotter key in and out. Just make sure you get the thrust washer back in like it came out. I always put a little grease on the splines when I go back together with it. There is a torque setting for the hub nut but I tighten it down till I reach the last hole the cotter key will go back in. You will be surprised at how much line is wrapped around the shaft if you have never done the process.... This can save some big $$$$$$$$$$$$$$$