First let us get the model and type corrected for parts look up. What you post for the type number is the date code which indicates that it was manufactured July 14, 2000. The type number is the number right after the model number and the trim number is right after that. These are usually found on one of the rocker arm valve covers.

As for the governor yes it possible for it come apart but not normally. More likely you just bump the static adjustment out of placed, The governor adjustment if not done right will lead to a racing engine and does take much either. What you need to do first is the static adjustment of the governor arm. If it still races after the following adjustment then it is a problem with the governor and someone would need to go in and replace it.

Static Governor Adjustment

1. With governor lever nut loose, rotate governor control swivel counter-clockwise as far as it will go (wide open
throttle) and hold in this position. Note this must done with the carburetor and linkages installed. Throttle control cable removed.

2. Rotate governor shaft clockwise as far it will go, Fig. 20.

3. Torque governor nut to 130 in. lbs. (15.0 Nm).

[Linked Image from i.imgur.com]

Now the starter personally I never had a circlip (retaining clip) to simply come off unless someone had deformed it not how to remove and install it. Here I just replace the clip with a new one and install it the tool that brought for just installing these clips but they can be install without it just much harder to do. Good news as these starter drives are the same unless you got a very old engine where they use a pin to retain them. Even the ones with the steel gear uses the same starter clutch. There is one drive that is different but I have yet to see it here.

But once we have the type number we can get right part number(s) that you would need for replacement parts. Also note aftermarket starters for these are available so don't need the OEM starter which can be expensive.