kohler magnum 18hp weak/loss of spark

[mark.aa]

have a argo magnum with a 1991 18hp kohler that wont start.
weak spark on rear cylinder none on front .
tested for spark with a known good plug.
checked and cleaned all connectors to engine,replaced some corroded ones.checked earth points,
disconected the 2 engine ignition interupt (earth)wires from switch.still the same.
is the flywheel pick up sensor part of the coil?
any ideas

[Gary F]

weak spark

Hey , did you get this running yet ? , no spark , weak spark is often caused by the magnets on the flywheel or coil pick up ends being dirty , rusty or corroded from sitting withought running , clean them up till they are shiny new and check for the proper gap , use a scotch brite pad with a little solvent to clean them off , useing steel wool will work but your going to get little peices stuck all over the magnets and you have to clean them off or they can short to ground , it's a pretty quick , cheap and painless .