Odds are the ignition is fine (please run through the ohm meter checks in the Factory service manual to confirm, though -- and use an Analog ohm meter).
Factory piston ?----Might as well take a cylinder head off and post the numbers / letters found on top of these pistons.
Yes, piston broke and then piston pushed broken piece through aluminum block. Broken piece came from intake side of piston/chamber. Motor still turns
Put the batteries in parallel as you wanted, but install a high power switch between them to enable you to isolate the trolling motor battery. So, when
Hole in the block ???----Any pictures of this hole ?-------A recognized repair shop or something else ?---Will the motor still turn over by hand /---With