Starter motor & crankcase questions

[willie]

The starter on my GK has begun making some pretty wild sounds when I'm cranking it. Like none I've ever heard before. So, I pulled the carbs off (I wanted to change the o-rings anyway) and removed the starter. Piece of cake. The 1st thing I noticed was the amount of oil pooled up under the starter. I was surprised to see a hole in the crankcase directly under the starter. The hole is a little smaller than the diameter of a dime and appears to be from the factory. I just looked at the parts diagram, expecting to see a plug for that hole but it doesn't show anything. What's the deal? Should I get a plug from the local hardware store and plug the hole or is it a vent and if so, where do I get the missing piece?
I hooked the starter up to my battery and it squealed when I spun it. My guess is that its time to replace the bearing(s). Since the parts diagram doesn't show the bearings being available I'd like to know what others have done. I'm considering going to a bearing house to match it or see if the local starter rebuild shop will rebuild it.
Your thoughts and suggestions are appreciated.
Willie

[tkent02]

That's the Mystery Hole. It's supposed to be there, to keep rain water or leaked oil from pooling up.

I have a good used starter, probably the same as a GK, it's from a GL.

If you want it, PM me so we can measure things and make sure it's right.

[Agemax]

yeah it is a drain hole to stop the starter "well" filling up. do not plug it up.
a second hand starter will be cheaper and less hassle than trying to rebuild your old one

[bwringer]

The oil is coming from the hardened o-ring on the nose of the starter.

It can also come from a leaky cam chain tensioner or oil pressure switch, but those are fairly obvious. The usual cause of oil from the lower Mystery Hole is the o-ring on the starter.

Oh, and here are some Mystery Hole pics. Yes, it's a drain hole and yes, it's supposed to be there mainly so your starter doesn't drown in the rain:

The Upper Mystery Hole:


The Lower Mystery Hole -- the tubing is only there to show they're connected:

[willie]

Thanks guys! Of course its a drain hole. Whata dumby I am. I wondered because at 1st look, I thought I was looking into the crankcase.
Also, BW, you're right about the sources of the oil. I did notice oil below the tensioner. I'll have to take care of that to while I have access to it.
Willie