1996 Evinrude 9.9 Four Stroke

I have a 1996 Evinrude 9.9hp four stroke electric start that I troll with. I am having a battery problem. The battery is new and it fully charges. When I put the boat in the water before I start my motor my voltage is at 12.4V. Once I start the motor it stays at 12.4 Volts. After trolling around for 6-7 hours my voltage starts dropping and by the end of the day it is at around 11.9V. Not sure what the problem is. My buddy have the same motor and when he trolls his voltage is always around 13V. I constantly have to charge my starting battery and I know I should not have to. What could the problem be?

Todd

Re: 1996 Evinrude 9.9 Four Stroke

If the voltage you're reading at the battery doesn't go up from the reading you got with the motor off, the charging coil in your stator or rectifier may be bad ... or it could just be a bad connection in the wiring.

Do you have a service manual? The manual describes several test procedures to determine if these components are within the acceptable resistance ranges.

Re: 1996 Evinrude 9.9 Four Stroke

You can check the stator coil for continuity between all the connections. I think I am right in saying that it has three yellow wires , one with a blue tracer and one with a grey tracer. You'll get double the resistance between the plain yellow and the yellow/ blue than between the other combinations.

When running you should be able to measure 12 volts AC or more depending on revs between the yellow and the yellow/gray and also between the yellow/grey and the yellow/blue (Don't know what you'll get between yellow and yellow/blue)

You can check the rectifier by following http://forums.iboats.com/showthread.php?t=190638 but if you use a digital meter use the diode test range not any of the ohms ranges.

The red wire is the positive output from the rectifier. If you get a reading between there and ground that rises with revs to well above the battery volts then you have a bad connection between there and the battery