Kohler K Series Starter Motor issues

[Anglo Traction 1,016]

Starter on my original 12hp Kohler in my '72' Raider 12 had begun to squeal more and more last year, so having built a spare Starter from 2 really iffy ones, I pulled the squealy one to inspect it and fitted the new spare to test it etc. 

The spare works beautifully........So last night I got around to tearing into this one to cure the problem and give it a clean up-

 

No sign of broken Magnets this time for a change, just a few loose flakes, Carbon dust and light rust areas from trapped condensate-

 

So generally all in pretty good nick really, note the date stamp on this American Bosch Motor (Dec 20th 1971).

 

The cause of the squeal I suspect was the Thrust washer that had been worn by the hard stop ring which has a gap and sharp edges . This washer takes a lot of pressure when the Motor is energised and combined with the dry Carbon dust and bare metal faces, starts the noises etc. Close up of the Stop Ring, Shaft bearing face and the 0.0205" (0.52mm) thick thrust washer-

 

The 'Cure' I hope will be the addition of another thrust washer of same thickness. I found just the right size/type in my box of bits and the Washer came from my fully rebuilt engine now in my C-120, when I scrapped the Balance Gears in it, I kept the spacers, washers and Snap Rings. All I had to do was increase the bore of it by 0.003" to just fit over the Shaft bearing diameter face with no slack-

 

So the new washer will fit on first followed by the old one and the same original way around. With the bearing plate in place un-lubricated and with hard pressure on it, the shaft rotates with no friction resistance at all, but will apply a small amount of High pressure Copper grease between them.

All the Brushes etc cleaned up nice and very little wear-

 

Commutator segments had the usual Carbon Glaze, so cleaned off with the shaft mounted in the Lathe chuck at slow speed, then a final air blast to get the dust out -

 

Body internals all clean now and found the magnets still have makers ink stamp on them-

 

I shall strip the old paint and decals off and give it a repaint and new decals before it goes back on the Engine.

 

So if you haven't been inside one of these before, don't junk it and look for another when it misbehaves........... Give it a Refurb birthday and a new lease of life. Hope this helps.

[neil 524]

Awesome description Richard , good to have you back ,

My stater squeals on starting , I guess that it needs a refurb like you have shown.

Fancy another one to do

Neil

[meadowfield 1,900]

Great instructions Richard

[Stormin 4,458]

Thanks for the write up, Richard.   Trust your feeling a lot better.

[Wristpin 400]

Would possibly question the use of a "copper grease" . The old maxim was "use grease for stuff that moves and copper for stuff that doesn't (shouldn't!)" still holds good. Copperslip and its equivalents are not a grease but an anti seize compound and perhaps a high melting point moly or graphite grease would be more appropriate in that application.

[Anglo Traction 1,016]

Would possibly question the use of a "copper grease" . The old maxim was "use grease for stuff that moves and copper for stuff that doesn't (shouldn't!)" still holds good. Copperslip and its equivalents are not a grease but an anti seize compound and perhaps a high melting point moly or graphite grease would be more appropriate in that application.

My mistake Wristpin, wrong use of words. So yes , disregard my reference to Copper Grease.

The stuff I have is an old Paste from Aviation industry (expired life date) that is a mix of Graphite and Copper, Graphite being the greater proportion as there is only a tint of copper. It is almost in crumb form so has little grease as a binder. If it is spread onto paper, it looks like HB pencil marks with a hint of copper/bronze and no grease soak in. 

Copper/Graphite mixes are used for Plain Bearings in areas of heat and pressure like Roller Beds in/out of Ovens etc, so I deemed this substance useful to fill the worn void in between the old and additional Thrust Washer-

 

There is also no Flammable grease in it. Kohler Manual does not mention any internal lubrication of the 2 types of Starter Motor (note the Induction Starter Motor version has both a Spacer Washer and a Thrust Washer fitted, where the Permanent Magnet version like this one has one Thrust washer as standard).

 

I don't use any of the mentioned Automotive brands from places like Halfords for brakes or Thread lube like Kopr Kote, too many issues with compatibility.

 

I have however put a small amount of Teflon Dry Lube on the Bendix end bearing faces of the Armature shaft and End Plate, as well as the Bendix Helix. This does not attract/absorb Dirt or moisture very easily and works well for me. The Bearings and Bendix Teeth on this Motor are in very good condition. 

The other Armature end (rear) has a Dry Oilite Bearing where there is a risk of spark igniton or contamination of the Brushes if grease was applied.

 

The Motor has now been reassembled after prepping, painting and decals fitted where it received a coat of Fuel proof Lacquer and now ready for fitting-

 

 

So just one thing to bear in mind and that is ...these motors are not Continuous Rated, so if your engine won't start/run after a max of 10 seconds cranking, leave it to cool for 1 minute before trying again or you'll burn the Starter out. 

............ I may well be parting with my spare one now Neil, I'll bear you in mind.

Regards

[meadowfield 1,900]

great work Richard, looks like new!

[Anglo Traction 1,016]

great work Richard, looks like new!

Thanks Mark. It's a gooden again.

Got around to swapping the Motor onto the Raider today and thought I'd try and do a (1st time) Video using my Son's Old Camcorder after finding the right software online.

'Ohnobucket' (photobucket) is a real pain for buffering lately, but I've put a link here anyway-

 

 http://i1190.photobucket.com/albums/z442/AngloTraction/th_Starter%20motor%20refitted_zpst600ns86.mp4  

 

Video sound is never the same as real time .