Question:
I just bought a slightly junky 1980 JD Liquifire. I'm getting no
spark. When I give it a good pull, the headlight lights up
ever-so-slightly. I can just barely see an orange glow. The plugs
are new and I've tried a bunch of times with them sitting on different
spots on the engine, so I'm pretty sure I'm making contact. Since the
light goes on, does that narrow it down to the CDI? Is there a way to
test the CDI? Could it be wiring?
Answer:
I own the same make and model. Try holding the throttle slightly open as
you pull on the rope, and see if the spark returns. If so, you have a loose
throttle cable that is causing the throttle safety switch to kill the
ignition.
You can unplug the 5 position connector (normally a white connector) that is
located at the side of the recoil housing, since the Kokusan ignition system
on that sled is normally open, and you have to ground it to kill the
ignition. So, when the 5 place connector is removed, it takes the ignition
switch, kill switch, and throttle safety switch out of the circuit.
Also, check to make certain that the individual red and white wires are
connected with no corrosion, and that the black 3-way plug is connected with
no corrosion, since those provide the juice from the magneto to the CDI box
to the ignition coil. Also check that the brown ground wire is connected to
the engine case.
If you need to adjust a loose throttle cable, make certain the the carbs are
properly synched on that sled, or one cylinder will do all the work and
you'll constantly foul plugs on the other one.
One oddity about that sled: It has an oil sump for the PTO gear. There is a
small sight glass on the lower front of the engine, and a screw filler to
put oil into the crankcase. If the vent hole plugs, the oil will get sucked
through the crank seal into the crankcase, and the oil sump will go dry,
which causes the PTO gear to overheat and fail. So, clean off that sight
glass and make certain that you have oil.
