Re: No spark / Lightwin 3hp
You said you replaced the coils, points, condenors and plugs, that is a good start.
So to take it one step at a time, I would recommend checking the following:
Coils and Plug wires:
-New or used?
if used, could possibly be arcing to the stator plate underneath, grounding them out
-3hp ignitions are prone to arcing right where the plug wires make the tight turn to go under the stator plate to the top side, due to movement of the stator plate to change throttle positions and often develop a chafed area most prevalent at far ends of the travel of the plate.
-Check where the plug wires bend severly at the bottom of the plate for evidence of black arcing marks.
-Did you fully insert the secondary (plug wires) into the coils, engaging the pointed post?
-Did you use the small rubber boot which insulates the coil to plug wire connection from the stator plate?
-If you replaced the spark plug wires, you must use wire core, and not carbon core (automotive) wires.
-If you replaced the plug wires (even if not) have you verified the spring contact inside the boot is clean, and properly piercing the wire core plug wires in the center?
-Did you check to be sure the primary coil wires (small wires going to the points) are not grounding out?
-Coils have 2 small wires coming out of them, one (primary winding wire) goes the the corresponding set of points for that cylinder. The second (ground) wire should be grounded under one of the coil mounting screws, swapping these wires would cause a no spark condition.
Points:
-Even if the points are new, they should be dressed (cleaned) using some fine grit paper (around 320-400 grit) you can dress the points, then clean them with some laquer thinner using a business card type cardboard dipped in Laquer thinner until it wipes clean through the closed points.
-Point gap, should be .020" on that motor.
-Points cam, on the crankshaft, there is a small, removable cam, it must be oriented properly (they are usually stamped "Top" ) on the side that should face up. Cam missing or installed improperly will cause no spark.
-Points properly positioned?
-Points have all the electrical connections for the primary side of the ignition, should have the condensors and coils primary wires connected securely to them. NOTE: they must also have the CORRECT cylinders components connected to them, swapping those leads will cause no spark.
Also, the 3hp motors had no kill switch, so there should be only the coil primary, and the condensor leads on each set of points, a third wire would indicate a kill switch has been added, if so, remove that wire.
Condensors:
-New condensors should not cause any issues, but sometimes (rarely) they can go bad. replace with known good, or the old ones to test if all else fails.
-Connections to the points must be tight, secure, and not grounded to the plate.
-The Condensor body should be securely screwed into, and grounded to the stator plate.
Spark Plugs:
The correct plugs for that motor should be J6J the new part number is J6C
-Plugs correct and gapped at .030"?
Chances are pretty good it is one or more of the previously outlined things to check that is causing your no spark condition.
I may have missed something, but these checks have all proven to be effective in issues I have encountered with no spark conditions on a magneto/points style ignition.
Good Luck.
