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Worn Rotor Pinion?

Tue Sep 25, 2012 1:46 pm

Hi All,

My Cub (not named yet) was running great and just quit. I have tried to start it many times, but have had no luck. Started working on the carb and now have more leaks than before.. bummer. I did some investigation on this website and decided to check the rotor and drive gear. The drive gear is badly worn and almost smooth. Are there possible issues that caused this wear? If so, what might be the cause of this?

BTW.. this website and the people I have talked to from this site are a tremendous help!!

Thanks,

Re: Worn Rotor Pinion?

Tue Sep 25, 2012 4:01 pm

The pinion gears do wear over time. If dirt gets in, that just exacerbates the situation and makes it wear more quickly. When you replace this, put a touch of grease on the pinion gear so that it has a little bit of lube. Inspect the rotor gear as well, if the pinion is worn, I hope the driven gear on the bottom of the rotor is OK...

Mike in Gibsonia, PA

Re: Worn Rotor Pinion?

Tue Sep 25, 2012 5:32 pm

I second what Mike said. I noticed TM(site sponsor) has both the rotor and pinion in stock.

Rick

Re: Worn Rotor Pinion?

Tue Sep 25, 2012 7:21 pm

It's good to see you here Brett! If you need any help just yell!

Re: Worn Rotor Pinion?

Tue Sep 25, 2012 9:26 pm

Mike & Rick... Thanks for the post. I think my rotor looks okay, but experience from this site says I should probably buy both. I have another question about the rotor pinion. It should be keyed on the backside of the gear correct? Mine is really worn and I noticed on the magneto the shaft is keyed.

Again, thanks for the reply!

Re: Worn Rotor Pinion?

Wed Sep 26, 2012 12:49 am

1968ranger wrote:Hi All,

My Cub (not named yet) was running great and just quit. I have tried to start it many times, but have had no luck. Started working on the carb and now have more leaks than before..



Systematic troubleshooting will save you hours of frustration and lots of money when applied to a situation such as yours.

A B C - Airway Breathing Circulation... Wait, that's for something else.

How about F A C S ? Fuel Air Compression Spark.

People have asked for my assistance more times than I can ever remember because their machine suddenly stopped running and with no systematic trouble shooting started turning this and turning that then replaced something here and something there and essentially had to throw in the towel because the original source of the breakdown was never addressed in the melee of parts swapping and adjustment turning.

If you trouble shot your problem down to the distributor, perfect. If it was a shot in the dark because the carb work didn't fix it, I'd cut my loss and start from the very beginning with F A C S and see where that takes you. Good luck.

Re: Worn Rotor Pinion?

Wed Sep 26, 2012 6:26 pm

As you've seen, there's a flat side on the pinion shaft, and the inside bore of the opinion is molded with a flat side also. It can be a little hard to see, but it's there. When sliding the pinion on the shaft, push easy, and rotate when it sticks, It will find the "happy spot".

Re: Worn Rotor Pinion?

Mon Oct 15, 2012 7:52 pm

Hi All... Just a quick update on my starting issue. I replaced the rotor pinion and rotor gear and was hopeful, but it still wouldn't start. At this point I was a little discouraged, but I then remembered that I tried to time the magneto prior to the rotor pinion and rotor gear replacement. My rotor pinion was worn badly, so I figured I would try to time the magneto with the new parts. The magneto timing process went as planned.. thanks to the video on You Tube. I then pulled the starter lever and she took off... music to my ears!

I now have a small chirping noise in the magneto/generator area of the engine and will need to figure that out, but I guess that gives me a good reason to be in the barn. Tractor runs strong and now I will need to come up with an official name. Thanks to this website and those that have helped with this post.

Re: Worn Rotor Pinion?

Mon Oct 15, 2012 7:58 pm

1968ranger wrote:I now have a small chirping noise in the magneto/generator area of the engine and will need to figure that out, ...

Check the oil in the Fan Assy and oil the generator.
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