Mercury 25 HP Battery Replacement

In 2006 I purchased a (2002?) Mercury 25 HP motor with electric start, along with a boat. It had a relatively new battery at that time, and the guy I purchased it from made a point of telling me NOT to disconnect the battery if it goes dead. But, I don't remember what he said the reason for not doing so was. I do remember he said he had done so, and it caused a problem that was expensive for him to have repaired.

My problems are:
1. Four years later, I have to replace the battery and I can find nothing in the Owner's Manual that indicates any difference between replacing this battery and replacing a car battery. It gives the proper order of disconnecting the battery terminals (negative terminal, first/positive terminal second) and reconnecting them (positive terminal first/negative terminal second). But, no mention is made of any unusual concerns or considerations.
2. If you're not supposed to disconnect the old battery first... how the heck do you replace it?

Was somebody pulling my leg? Or, is there some reason why an unusual procedure is required to replace this battery?

Re: Mercury 25 HP Battery Replacement

Replace it like you would a car battery. I'll bet he said don't disconnect it WHILE THE ENGINE IS RUNNING. That is still true.

Re: Mercury 25 HP Battery Replacement

usskydvr,

Thanks for responding. I think that's what I'm going to do.

Since I originally posted, I tried jumping the old battery (which tested bad) from the new battery... and nothing happened when I tried to start the engine. So, apparently, there's something else wrong, too.

I failed to mention I didn't use the boat last year... or, so far this year. I'm thinking moisture may be a factor.