Starting battery DYING

My starting battery for my motor is dying, but the battery seems to be fine since it holds a full charge. Anyone ever run into this problem? Thanks

My battery acted the same way. Load test showed us was borderline. It would barely crank my 90hp Merc. I replaced it with an AGM.

Have a "draw test" done. Auto shop have them, or buy one for future use. They are not expensive. It look like a cheese grater with battery clamps. It tells the actual condition of the battery. A battery in poor condition can still read 12 volts, buy the draw test will show immediately if the battery is good or not.

How do you know it's bad..if it hold a charge

Makes no sense..good luck

Smh

No thanks, not interested in free advertisers opinions

I have never had a set fail in less than 5 yrs. The biggest dump was spring preps. Sitting on maintenance charge over the winter. Point is check it.

msk,

If that's the case (1/2 gallon a battery) you need to be checking way more often. If they get that low you are just killing the batteries. 

Pull the caps and check fluid levels. Add if needed and recharge. Maintenance free is not true. May not be the case but I have 4 31's on my boat and 2 times a season check them. Every time I have checked, fluid was needed as much as 1/2gal per battery at times. 

What do you mean by dying? Do you run many accessories off the starting battery? If you do some anchor up fishing and run a locator and or live well pump off the starting battery it can draw it down to a point where it acts weak when cranking the outboard, size of outboard matters also. 

On my boat if I leave the key in the ignition even in the off position it drains the battery, never figured out why, so I take it out.

A battery can take a full charge and still die quickly when placed under a load. How old is the battery? Might be time for a new one.