Starter and ring gear replacement?

However, I'm all for preventative maintenance, and have no desire to push my luck with the starter and ring gear as far as it will go. Hence my question: is it time for replacement, based on my experience and the pictures below? The ring gear and pinion both look to me like they have been worn down somewhat (see the rounded front edges/tips of the gears where they engage each other), but based on the wear pattern on the rest of the pinion gear it seems the two gears engage reasonably well (the black wear pattern on the pinion gear teeth seems to extend reasonably far into and down each tooth). Should I replace either, or maybe both? Or is the starter plunger perhaps just occasionally not extending fully and hence causing the gears not to engage properly, resulting in the grinding? Which can be solved with a starter rebuild, and not gear replacement?

Thanks a lot for any opinions and help!

Ring gear close up:

Starter:

Pinion close up:

Okay, thanks, so they're not just worn like I first assumed. I'll get stuck into cleaning and testing the starter.

Thanks Ken. 'Worn down' as in should be replaced, or 'worn down' as in should be good for another couple of hundred hours of boating?

If I pay up for shipping via Fedex or the like I should be able to get a new ring gear easily enough.

So............ I think me and Pete took turns being right and wrong a couple of times maybe  

After looking at a new 157 tooth ring gear there is no difference in the bevel of the teeth from one side to the other.

However.........there is a bevel on the ID of the gear on one side, so if you try to flip it, the gear won't sit in the same spot on the flywheel and will give you problems

First picture is the teeth and the second is the bevel on one side of the ID.

I'd probably get a new ring gear since everything is apart right now and not have to worry about how long the present one will last.

I have lotsa parts hanging around. And.......I've uh broken lots of stuff too.

Some day I might achieve the "supreme hoarder" status of Gary S...........maybe

BTW  A part number you could cross reference is Pioneer FRG-157N or ATP ZA-503

Tough job- but someone has to do it. 

As to the Arco starters they seem pretty good.I have not had the one very long but it has had alot of use. The GT40 I picked up already has one on it. They are light and easy to install.

Thanks - I placed my order for a new starter and ring gear from Nautiqueparts.com on Monday.

Torque is more important, go over it two passes

and really shouldn't be oil slinging around anyway, else there is bigger problems.

I'd leave it alone  

After a couple of hours of playing with flywheels and ring gears, it seems that the stock ring gear doesn't have that big pronounced bevel on it.

Both sides are the same on the stock one..

The aftermarket one that's in the picture has the bevel, but I put it on a flywheel and did some measuring and it sat at the same depth whether it was put on bevel first or bevel facing out.

I'd imagine some aftermarket ones have the bevel and some don't.

It looks like the bevel is there to make installation a little easier. With my swapping it helped to center things compared to the no bevel side going on first.

Pictures still to come if you need more

Since you can see what you have, maybe going with your gut would be a good thing.