2005 mercury 9.9 hp bigfoot motor

Depends on the HP of the motor. The long shaft will only ad a few lbs. See this link for motor specs on weights.

https://www.nadaguides.com/Boats/2005/mercury/outboard-motors

Hi,

Did you check if there is anything obstructing movement inside the printer?

Without seeing it I would suspect you need to replace your lower unit.

Sounds like perhaps the splines on the torque converter output shaft may have failed, there was a recall on some of those for that very issue. Here is a news article about the issue:
Ford is recalling certain model 2004 and 2005 Ford Freestar and Mercury...

Have you checked your intake cam. Mine started clicking when my cam got wiped.

The rattle is caused because the rpm is lower. When stopped in drive with one foot on the brake, press the throttle down slowly until the vibration stops and the noise goes away. Cause? Weak or bad motor mounts, loose bolts or parts.

This sounds like the front drive shaft that may have worn u joints. Put the vehicle in park, set the brake and proceed to shake the front drive shaft up and down to inspect for wear. Let me know what you find.

Could be , some props have a pressed hub

please can you specify whether the sound comes from the engine or the tyre or some other part of the car

do you have a mechanical or a electric fan?
acording to your question seems to be electrical make sure the fan nut is tie and there is no cracks on blades
also wigle the ft shaft up and down and if you feel any play the replace the motor