I have been working on an old spare Craftsman GT/18 lawn tractor (ROPER). It has a Briggs 18 HP twin engine model 422437. It won't start because of an erratic, weak or a no spark condition. The coils check good with an ohm meter and are silimilar in readings. . The kill switch wire on the coil is disconnected for test purposes and I use the engine's starter to crank the engine during tests. . One of the two cylinder's spark is worse than the other with this. I have tried two separate new "magna coils" , all behave the same. I set the air gap from .010-.012". I have even flopped the new coils over and tried without success. I have sanded the light coating of rust off the flywheel magnets and the magneto's mounting surface on the block. too. I am starting to lean to a flywheel magnet issue, what do you think?
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