115 Merc

[Fishin4fun]

I am not getting the proper recharge from my motor. I have a 1985 115hp What do I need to replace to get it to charge my battery? I think I am getting a slight charge 12v charge, but after running my trolling motor for a while or if I idle the motor and run my trolling motor, the volts continue to drop. My clymer and Seloc manuals dont cover this very well.

 

[LubeDude]

Re: 115 Merc

Do you have a volt meter in your dash? It should read between 14-16 volts when you are running accross the lake. Most charging systems will not keep your battery fully charged if using accesories continually, thats why you need at least two batteries, I have three on my Bass Boat. Two for the 12 volt trolling motor (which are not hooked up to the engine charging system), They are charged when I return home separatly. and one for starting.

 

[quantumleap]

Re: 115 Merc

LubeDude is correct. The engine cannot compensate for the drain of the trolling motor. Run your accessories off a separate battery.

 

[DJ]

Re: 115 Merc

Engines of that vintage had 6 to 9 amp charging capability-at best. That small rate of charge would require 3000 rpms or better to accomplish.<br /><br />A two battery system is a must for a rig, such as yours.<br /><br />Checking for proper charging is still a good idea though. You can do that by putting voltmeter leads across the battery + and - and see what it charges, at planing speeds.