Hello all!  Looking for some advice getting my pony to fire off and run correctly.  Originally the starting motor was locked tight on my D8 13A, so I tore it down to freshen it up.  I lined the gears up between the cam and crank (put the "C" on the crank and cam together) but was unable to find the "M" marks on the gear for the mag and the "M" on the crank gear.  Not gonna lie marked everything the best I could during dissassembly and reassembled. Finally, about 5 months later got around to trying to fire it up and can't seem to get it to ever hit on both cylinders correctly.  Either backfiring horribly thru the carb or just hitting on one for about 30 seconds and dying off. tried turning the mag 180 and it does better sometimes. Believe the cylinder closer to the radiator is number 1 or is how I'm running it.  Have replaced the plugs and wires also reset the point gap to 015.  Wico mag.  Looking at the mag mount would anyone happen to know if the slot it mates into should be pointing up and down or horizontal when initially timing the geartrain.  Believe that is where my problem is but without the "M" being visible on the gears it is proving to be quite the challenge. Have rotated the engine many times with a borescope watching and can never see any markings other than the "C" as it comes around.  

If you cannot find the marks on the gears you need to time it with the impulse. Spin the gear until it clicks over and makes a spark on #1. Be sure the #1 cylinder is on Top dead center. (TDC). Drop it in the hole and you should be good to go.

Thinking here. It has been a while. C may be for clockwise rotation. If the mag does not have an impulse then you have to know when the magnetic fields break and the points open. Are you sure the valves are times correctly? They should open on intake and close on exhausts as the piston is all the way up and 180 out on ignition.
 

Just a thought did you use solid copper wire for new plug leads. Modern carbon leads don't work well on magnetos.

I believe after a little digging I thinking I've got to time the mag drive gear somehow with this style mag. I have attached some pictures of what I'm working with.  I know you can adjust the rotor but with the "MAG" markings lined up on the flywheel it should be at the point where it's breaking the points I believe.  You can only mount it one of 2 ways to the drive coupler. According to the repair manual there should be an "M" stamped on the gears but I sure can't see them anywhere.  I am using Champion UD16 plugs and new solid copper wires. thanks again for the help.

According to my Wico to Cat magneto conversion chart
XH1908 is for early D5,D6,#12 and is clockwise rotation
The D13000 uses XH2837 counter clockwise rotation and replaces the American Bosch MJK 4/2 180 D311

I was wondering if it was the correct mag. something just doesn't seem right with it.  This evening i pulled the timing cover assembly off and was able to find the "M" on the crank gear and I believe the mark on the mag drive as well'(honestly don't know if I had it right the first time or not but it is for sure now). When we bought the dozer, the pony was locked up tight and someone painted everything, so I just assumed it was correct mainly because the rest of the machine is in such great shape and was defiantly a well-cared for machine. I can confirm that the mag drive does turn counterclockwise so possibly it has been the wrong mag this whole time.  Ran out of time this evening to try to see if it would run any better.  I know while trying to set the rotor looking thru the little window there is no way to get it in the center of the

window. Can't rotate the mag or the rotor to ever line up perfectly. I guess I need to be on the hunt for the correct mag for this engine. Anyone happen to have any leads on one sitting around?

Need to confirm that Mag number. I read it as XH-1908 but if it is XH-1906 it is an older correct unit for the D13000.
Can't quite make it out for sure in the picture.

Hello Old Magnet, I downloaded the photo to my desk top computer. When enlarged enough it definitely reads XH-1906. Nice catch.
Craig