The .040 on the plugs is too much. The petronix is not a high performance ignition. Its just a different way of triggering the ignition. Instead of the opening and closing of the points to allow the coil to do its job, the petronix does the triggering. So there is no spark enhancement. These 235 motors can sometimes be sensitive to gap size given the position of the plug tip high up in the funky exhaust pocket. The wider gap just makes it harder to get the best spark. Try going back to .035.
