Have Boat Questions? Ask a Boat Repair Expert.
First thing, remove the engine cover. Watch the pinion gear on top of the starter and see if it engages the flywheel. If it just spins, with the key off turn the pinion gear by hand and see if it travels up the shaft. If not put a dab of grease on the starter shaft and move it up and down.
Check the voltage of the battery. What is your voltage? Is the battery in good shape, fully charged?
Check the battery cables are secure and clean with no corrosion, particularly the ground cable.
Post back what you find and we can go from there.
Please let me know.
Great, standing by.