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DIY Starter Commutator Repair

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#1 Sawdust OFFLINE  

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Posted April 14, 2015 - 05:16 PM

My starter on my MF 12 looked pretty bad. It was con-vexed to the point where the brushes were not making good contact & made the starter start & stop or not run at all. I don't have a lathe so I improvised a little & came up with this contraption that worked well. 


See the damage to the inside area.

Starter repair 2.jpg


Make sure the drill is level with the armature & supported well to get a true flat running surface before filing. Remember this is your lathe :D I started out dressing up the high spots on the edges first.

Starter repair 1.jpg Starter repair 3.jpg Starter repair 4.jpg


Once I got the high areas down near the center I used a flat file to dress up the center. I'm 60 years young & every time to this day I use a file I can hear my metal shop teacher say " don't file backwards boys just on the forward stroke". He always drilled us about how it would ruin a file dragging it backwards on the work piece. After this I used some emery cloth, 400 grit paper & then steel wool. Make sure you blow clean it well if you use the steel wool so no metal particles give you a short later. I also went back & cleaned out the space in between the copper plates with a thin screw driver.

Starter repair 5.jpg


 I'm sure this has been done before but I couldn't find anything about this repair other than using a lathe. Thanks for looking!

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#2 EricFromPa OFFLINE  



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Posted April 14, 2015 - 05:38 PM

HEY I JUST did something like that to the starter on my old Sears today.It's the same old style Tecumseh starter to.Mine wasn't quite as bad as yours but it was really dry and squealed like a bunch of piglets.I chucked mine up in the drill and cleaned it up with sand paper then polished with emery cloth.


Make sure you clean the burrs out from between the commentators to keep it from shorting.I used the Back side of my pocket knife and gently scrapped at it till the burs were clear and the gaps were fairly even.


They're good hi torque starters when they're working correctly.

Edited by EricFromPa, April 14, 2015 - 05:38 PM.

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#3 Sawdust OFFLINE  

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Posted April 14, 2015 - 06:16 PM

LOL wonderful minds think alike don't they. I did clean up between the commutators like you mentioned. Thanks!

#4 JBRamsey OFFLINE  

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Posted April 14, 2015 - 06:16 PM

Shop teachers and files. Our first project was to make a hammer head by hand. We had to file it flat within 3 thousandths and polished it with crocus cloth. Those skills are still me today and my neighbors are baffled what you can do with agile besides sharpen things.
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#5 propane1 ONLINE  

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Posted April 14, 2015 - 07:46 PM

Thanks for the lesson. I remember the file teaching too. I had a bad starter on my Mf 12. Could not get it to work good , so bought a new one. It then after a year or so acted up. Cleaned it up, had do do it twice. Not to bad now. Starter was over $ 200 at the time. Still have the old one, just in case. !!!! Noel
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#6 Bill 76 OFFLINE  

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Posted April 15, 2015 - 01:39 AM

That worked great and yes I remember the filing in shop class also,weeks of filling on a hunk of steel all the while staring at the bench grinders thinking there's got to be a better way but it was a lesson well learned. 

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#7 crittersf1 OFFLINE  


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Posted April 15, 2015 - 07:38 AM

I do that all the time in my drill press. Thought I was the only one.

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#8 pTrevor OFFLINE  

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Posted April 23, 2015 - 01:29 PM

Thanks a lot for the thread here. I had to repair my ctarter too some time ago, but I couldn't. So, I decided just to get a new one from tractortool store. Next time, I will be able to make it on my own ;)

Edited by pTrevor, April 23, 2015 - 01:29 PM.

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#9 det12187 OFFLINE  

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Posted September 25, 2015 - 11:46 AM

Hack saw blade will also work for cleaning out spaces between commutators if the space is that wide, this is called

under cutting. I have done this file method many times on generator commutator while in the AirForce, works good.