Big mistake removing GOOD old batteries.
The newer ones are DESIGNED to fail in much less time and number of run down cycles.
Yes They can really build them to die on a certain year after construction.
LIFEPO4 batteries......MUST ...... have the correct charging and... COMPLETE CUT OFF... voltage in the charger.
No trickle charging after battery is fully charged.
TOO RISKY that way.
I do it the way all marinas do it. I drain ALL the drain fittings on the engine. No cooked rubber stuff and no ice ups causing damage. Millions of boats get the safe ....open the drains way. every winter.
Dealership is still a bad place. To have to get outside help for the engine being too high. (n)(n)(n)
Do NOT NOT ever let that dealer EVER EVER come near your boat. Same for buying parts. LOSERS You will be sorry
My 1986 and 1999 Evinrude's both start instantly hot or cold.
Remember the starter cranks the engine fast. Enough to almost fire 10 times per second. So any bad mixtures are pumped out instantly.
Neutral Safety Switch or Man Overboard Switch ?
Get a cell phone and a Emergency V H F radio and fold down antenna.
Describe your boat. Does it have a dashboard or side panel ?