Magnum 20 Help?

[HorseHead1089 99]

Hey guys, Recently got a magnum 20 from Aldon, kudos to him for the good deal, anyways i started to tear off the tins and carb and unfortunately snapped a carb bolt in the block! My friends father (Mind I'm 16 for this to make more sense) who i'm working for parting out tractors, has offered to help me out with this motor as this is my first experience with a twin after basic tuneups on a farmall super A, valves and basic maintenance of carb, oil, filters ect, on a 17.5 intek B&S, a lot of ignition work on a 11hp briggs off a C-111 and two carb rebuilds and Governor adjustment on some K161's. This motor is a little crusty, dusty and greasy but looks to be good. the overall color is black, but the other colors i found are red and yellow, so im thinking this cold have come off a gravely or something like a 2072 cub cadet. my orignal intention for this motor was to be swapped on a cub cadet original, with each exhaust port with its own stack on each side of the hood. But now with the arrival of my grandfathers cub 100 and a good deal on a wheelhorse the original gets the boot as i also have to work other expenses into this like snowmobile and gas money for buying parts...

So back to the mag.
The pto shaft measured to somthing like 1.435 or 1.425 inches diameter and i think somewhere in the diameter in the manual says 1 3/8"
So one of my first questions is what would the cost be of turning down that shaft to 1" or 1 1/8" and where to do that. also would i have to re-key it or does that happen just from turning it?
Also I imagine the crank would have to be taken out to do such, but is it worth it to take it apart just for that, unless i plan to use the mule drive? I don't need to mow with it or blow or till as i dont have any attachments. if so it'll probably be a plow and be used to tow and haul. Any other Pto options without turning the crank? So do you think i should get her running first, or just tear her down? Also the ignition seems to have delamiated? is that glue able or can be used as is? Also i went to my local shop to see about a carb rebuild. and a appears they are all discontinued for the M20 under wheel horse, gravely and Cub. So is there a carb kit that supersedes it or a different carb that will work with the motor and available rebuilds for? AND there are some wires hanging around, and an oil pressure sensor. if those could be explained that would be cool. Anyways thanks and here are some pictures.
 

[Thor27 722]

If it has a readable tag on it still, it should tell you the spec #, this can go a ways to i.d. where it came from.  It will be like 495__ . If you try that number into parts tree it may help.

http://www.partstree.com/parts/search/models/?searchTerm=kohler+m20


As for a carb kit, if you can't get it local, and I hate to suggest this, but look on ebay.

http://www.ebay.com/itm/Carburetor-Repair-Kit-KOHLER-KT17-KT19-M18-M20-K482-Rebuild-Overhaul-carb-/390035878778?hash=item5acff3337a


I wouldn't even consider turning and keying the crank, but maybe that's just me... 

 

Edited August 12, 2015 by Thor27

[HorseHead1089 99]

Thanks for some words of wisdom, however, is the number your referring to on the shroud or cast in the block, because the decal on the shroud was accidentally ground off when in search of it.

[Thor27 722]

I believe it would have been below the spark plug on front cylinder tin cover.  Myself, I wouldn't pull it apart if it's a runner.
The second picture is the rectifier, you need it.  

  

[HorseHead1089 99]

Yeah im Lookin to tow and plow with that motor, so also I'm trying to weasel my parents into swapping tractors to end up with a 416-H and I am buying a spare 310-8 so I won't have a problem with workin tractors.

[wallfish 15,960]

So back to the mag.
The pto shaft measured to somthing like 1.435 or 1.425 inches diameter and i think somewhere in the diameter in the manual says 1 3/8"
So one of my first questions is what would the cost be of turning down that shaft to 1" or 1 1/8" and where to do that. also would i have to re-key it or does that happen just from turning it?
Also I imagine the crank would have to be taken out to do such, but is it worth it to take it apart just for that, unless i plan to use the mule drive? I don't need to mow with it or blow or till as i dont have any attachments. if so it'll probably be a plow and be used to tow and haul. Any other Pto options without turning the crank?
No need to do anything with the crank, Just get a new pulley to fit that crank to drive the transmission since you are not going to power any attachments.

So do you think i should get her running first, YES or just tear her down?

Also the ignition seems to have delamiated? is that glue able or can be used as is?
It can be used like it is BUT will continue to get worse over time. I would drill a hole through it and use a bolt and nut (10-32 ) to hold it together or tap threads into the hole.

Also i went to my local shop to see about a carb rebuild. and a appears they are all discontinued for the M20 under wheel horse, gravely and Cub. So is there a carb kit that supersedes it or a different carb that will work with the motor and available rebuilds for?
Pull the carb off and give it a THOROUGH cleaning and reassemble it with existing parts. Find a rebuild kit and gaskets if that doesn't work.

AND there are some wires hanging around, and an oil pressure sensor. if those could be explained that would be cool. Anyways thanks and here are some pictures.
Two wires come from the stator to charge the battery They are the wires going to the AC ports on the rectifier/regulator. That middle wire of the connector is your DC voltage to charge the battery.
A wire from the coil is for shut down of the engine and grounds the coil for stop. (usually white)
Oil pressure sensor, when connected and working properly, will shut down the engine when oil is too low  

[HorseHead1089 99]

Hey perfect, exactly what I was looking for thanks man. Maybe in a little bit I may reveal my project....