Small Engines (Lawn Mowers, etc.): Getting MANTIS tiller to START, spark plug wire, retirement budget

Question
We own a MANTIS tiller Model # 722M, engine # SV-4/B355876, E, Koritz Corp Made In Japan and this season we CAN NOT get it to start! We have been in contact with MANTIS doing the following things (but not specifically in this order)

Dumped out fuel
Cleaned gas tank
Added New fuel tank grommet and 3 new fuel lines
Added New  “in tank” filter
Added New Start/Stop switch
Added New Spark Plug
Added New Choke Air Filter
Cleaned the muffler screen
Added grease to Worm Gear Housing
Added New Purge Bubble to Carburetor
Disassembled and sprayed carburetor with cleaner spray
Completed a “re-build” of the carburetor (diaphragms, needle valve, screen, etc)
Bought New gas container, doing proper fuel/oil mix


During all of this we had a couple of instances where the engine did try to run, but now it just won't kick over. It seems to be getting fuel, because after many pulls on the start cord the spark plug is fouled with gas.

In checking for a “spark” there doesn't seem to be one. This was done by leaving the cap wire on and shorting out the spark plug outer shell to the engine, with no apparent spark in the gap.

In looking at the exploded view of the Starter, Pawl Catcher & Clutch diagram I see references to an Ignition Coil, Coil Spark Plug, Cap Spark Plug, Pawl Assy Starter and Pawl Starter. Are these the parts that create the “spark” for the plug to ignite the fuel? If so where could we find these parts, and how difficult would it be to replace these, if this were the problem.

We would appreciate all of the help and suggestions to get our tiller running again. We are retired and need to look for help in all areas trying to stay within our retirement budget.

THANKS IN ADVANCE FOR YOUR HELP!  

Answer
We have never found a bad Mantis coil but since most coils are made by the same manufacture it's possible it is bad.

Remove the top starter housing to expose the coil.  There should be a spark plug wire and one other small wire that runs to the shut-off switch.  Dis-connect the small wire connected the engine shut-off switch and then check for spark.

Let me know what you find.

Eric