Although this is an old thread, but since people are still interested, I would like to share my experience.
The culprit to this weird noise is the starter plunger mechanism got dirty and dried up over time. So the gear can't rotate smoothly anymore and cause the noise. There is nothing wrong with the starter function.
There is a design flaw for this starter. Not the starter itself, but after installed on the vehicle, this flaw will allow the dirt and water to enter the plunger assy, and over years it will cause this problem. Acura corrected this flaw in 04 model though.
Simply put, you need to clean up the plunger assy and put seals onto the starter.
So you need to have some mechanics experience to tackle this task.
1. brake parts cleaner
3. weather strip, probably 1/2" wide x 1/2" thick. Black foam type should be ok. It should have glue on top and bottom sides. You can get it at Home Depot.
What you need to do :
1. take the starter off. You will see the gear and shaft are dirty and dry.
2. disassemble the starter.
3. thoroughly clean up the plunger assy, at least. I also cleaned up the whole thing, since I am in there already.
4. lightly grease the parts.
5. re-assemble the starter.
6. cut off 2 pieces of weather strip so it fit onto the 2 small rounded surfaces. These 2 surfaces are located on the top and bottom of the gear shaft, not where the bolt holes located. Use alcohol to clean the surfaces before you put the strips on.
7. install the starter back onto the car.
The starter should function flawlessly now. And the weather strip will seal the gap between the starter and engine to prevent the dirt and water from entering the plunger assy. This should make your starter healthy for years to come.
Refer to the following image.
Items 30 and 31 are the gaskets you are making using the weather strip.