225 EFI makes quiet winding sound when starting

[wjhuskey]

I have a 1998 Mercury 225 EFI on my boat. It's always ran great but it had been randomly giving trouble when starting. It would start great almost every time while out fishing, but some of the cranks would be a very quiet winding noise. Then it'd start fine on the next try. This would happen about every 6 or 7 cranks. Finally one day while out, this very quiet winding sound is all it would do, every attempt to start. My guess is something to do with the starter but wanted to ask for advice here. Thanks in advance.

 

[racerone]

Have your battery load tested.-----Cost no coins at many stores.

 

[wjhuskey]

Thanks for the response. Since you mentioned the batteries, I'm now wondering if low batteries alone can cause this quiet winding sound because I've recently had battery problems - when I got ready to winterize the boat (a couple months after the engine trouble) the motor wouldn't lower to drain any possible water from the lower unit. The onboard charger showed batteries were charged. Turns out, all batteries tested good besides 1 and the charger is obviously not working. I charged batteries separately with a different charger and motor lowered. Maybe I should try cranking the motor now to see if that was my problem? Think it was?

 

[racerone]

I like to trouble shoot.------Start with the simple stuff.-----Charge batteries or have them load tested.

 

[Faztbullet]

Being a 1998 it likely due new brushes and bendix

 

[wjhuskey]

UPDATE: I finally got time to try to diagnose the problem again. I tried starting it after I charged the cranking battery with a charger I knew worked and it made same winding/humming noise. Finally decided to test the battery today and it tested bad - it is only a 1 year old battery! I then put a different battery on it and it is cranking fine. Proud I didn't order a starter just yet. I never thought about a 1 year old battery already going bad, but it happens. It was lowering the motor after charged up but still a bad battery. Thanks anyway for the help guys