Small Engines (Lawn Mowers, etc.): Tecumseh - No Spark, crankshaft diameter, rotary corporation

Question
John,
I have come upon a Sears 21" Reel Mower(536-81760 PE4) with a Techumseh(143-243042 ser 33620) engine.  It has not been started in several years.  I removed the carburator and soaked it for several hours, freeing up the "butterflys" in the throttle chamber, etc.  Put new sparkplug in, cranked a couple of times, no spark.  Disassembled down to magneto, condensor and points.  Is there a way to determine which component is failing or should I just go ahead and replace all three pieces.  I'm a little concerned, the condensor and magneto are connected with a common wire, which connects with the points, but looking on Sears website, they only have the condensor listed, the magneto is not available.  I have another Tecumseh engine, what are the chances that the magneto would be interchangeable?  This particular Tecumseh(143-243042) looks like a vertical engine, but it has a horizontal shaft coming out of the bottom of the engine(top side of mower deck) that drives the reel.  Does Briggs make a similiar engine?

Answer
Hello Grady:

Most Times when the Engine has a Point Set the Condensor is the Cause for No Fire. Replace the Point Set. I Suggest you Use the Replacement Solid State Ignition Module. I us the Nova ll from Rotary Corporation. The Part Number is 8786 and can be Ordered or Purchased from your Local Small Engine Service Center. The Cost for this Unit is Not Much More than the Point Set (May not be Avaliable) and Gives Less Problems than the Point Set. A Replacement Engine from Briggs will Bolt to the Mower. The Only Worry is the Crankshaft Diameter and Length and the Keyway. Try Cleaning the Point Set Contacts. Then Set the Point Gap to .020in. Make Sure the Point Set Plunger is Extended when Setting the Gap. The Magneto to Flywheel Gap is Also .020in.  Hope this Helps. I am Here if You Require More Assistance. Let me Know What Happens, Please. Thanks.

Good Luck

Respectfully

John