Re: 1969 johnson 25hp coughs and sputters
Check the quality of the spark, too. Buy a $10 gizmo at the auto parts store that lets you test spark strength. It's about half as long as a ball point pen. It has an aligator clip on one end and a nipple for the spark plug wire to attach to on the other. You take out the sparkplugs, attach the aligator clip to a good ground on the motor block, put a spark plug wire on it, and pull the rope. The spark jumps an adjustable gap. It should jump a 3/8" gap with a bright blue "snap!". If it doesn't you most likely have a bad coil. An easy enough fix if you're handy; they sell coils here in the iBoats store. On a 1969 the coils are often cracked and leaking current unless they've already been replaced. The replacements are better than the originals. If you have a bad coil you will have to pull the flywheel to replace it. That'll be another $10 for a cheap puller and a couple more bucks for three 3 1/2" long 1/4" 20tpi grade 8 bolts.
