I'm not buying the "don't have time to get a manual" excuse, LOL, get the fargin manual NOW ! LOL, Ok jokes aside, a servicemans reference book for your tractor serial number is most likely easily found on E-bay or Midland Press, especially for a D-7.It does explain the procedure. What serial number is the tractor, does it have the 2 cyl. vertical starting engine and have the D-8800 4cyl. diesel ?, or is it a later series like a 17A and up. If it is a 3T, 4T or a 7M, heres what you need to do: #1 cylinder is on the left, closer to the radiator, pull the spark plug and put a cork in the hole, pull the inspection cover where the pony flywheel is and turn the motor over until you see the tick mark on the flywheel approach the tick mark on the case, top dead center of piston #1 is what you are looking for on the compression stroke, the cork should pop out. Ok, now you need to mount the mag, the way I did it was spin the mag by hand and understand the spark cycle it goes through, meaning, I turned it over by hand and noted when it fired a spark. It winds up with tension, then releases a spark, I think it skips a turn and then fires the next spark. With that in mind and the tick marks lined up ( I retarded mine a little actually) I mounted the mag to the starting engine coupling with it set to fire a spark when the tick marks lined up, #1 piston top dead center. It seemed a little tricky to get the mag to couple with the starting motor and have it match the postion I set it at to fire a spark. You'll see what I'm getting at when you look at the end of the mag and where it mates to the starting engine. I'm not totally educated on the inner workings of this mag, but I think they can be assembled to be 180 deg out, hopefully that is not an issue. I had trouble timing a rebuilt one to mine and ended up pulling a spare that worked and doing the above, it fired right off. My rebuilt one may need to be double checked for timing I could not get the pony to run with it and it was sending a nice blue spark. I spent a few days trying to figure this out, but with some persistence and luck with that spare mag, it worked. The servicmans reference book does not tell you which cylinder is #1 must have been an oversight, but there are operator instruction manuals, parts catalog and a seperat D8800 engine manual covering the D7, gensets, and marine applications specific to the D8800, which are indispensible for this machine, a must get if you plan to work on one of these, just a FYI on the information available. Also, use solid wire plug wires, not much faith in champion plugs, Autolite or NGK seem to be a better choice, these 2 parts are critical to delivering good spark and this low voltage ignition system needs a good delivery system to fire a hot spark, which is key to making these run good. Make sure your fuel system, tank, lines, sediment bowl are clean, if fuel is contaminated or restricted, it won't run well or at all. Hot spark and plenty of fuel to the Zenith carb, speaking of the carb, make sure it's clean, and working properly, needle valve and seat clean, float working, bowl clean, all little passages are clean. IMPORTANT, these carburetors can leak down and allow your crankcase to fill with gasoline, thinning the oil enough to seize the motor. When running the pony, as soon as the diesel fires, I shut off the valve on the sediment bowl, and then pull the drain plug on the carb, bowl, actually now I have a petcock in place of the drain plug and drain the bowl into a can to insure no gas can leak down at all. Keep that motor oil up to the right level, and clean, there is no oil filter on these and you should be using a non-detergent oil, allowing contaminants to settle out as opposed to being suspended in det. oil Not to say you can't run det. 30 wt. or heavier I have, but I changed it very frequently, these little motors are not tolerant of too much neglect at all, they will toss a rod or spin a bearing if the oil is thinned or low, but with some good care there is nothing like them for a cold start, they are only dependble if properly serviced, otherwise they can be really tempermental. A trick I use to change the oil on the pony is by cleaning the immediate area including the track, spraying it down to eliminate dust, then pull the side inspection cover above the oil sumps, use a Napa drill pump to suck out the oil, then blot up and clean the crankcase by hand, taking care not to let any contaminants get in, the drain plugs on the sumps are a real pain to get to on D7's, this makes it easier. Ok, I'm hoping this is some useful information ! Post your progress, hopefully it goes together easily.
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