Chain Runner

ok motor is a 99 500 EFI that i put in this spring. i bought a new battery because it was time, and the boat was running, however the volt gauge was reading around 11 volts at idle and got up to around 13 when on plane. i didnt think much of it until my batteries seemed to get worse each time. well after not starting after immediately shutting it down 1 day, i figured the alternator was bad. So i replaced it with a new one, still no charge...It puts out 11 volts at the terminal on the back of the alternator at idle, seems low. the exciter wire was also putting out 11 volts at idle, is that low? i checked and made sure the ground it sill hooked up to the bellhousing, it is. the connections seem to be correct at the starter as well. am i missing something?

wannabe

There may be fusible links you missed that are burned.

Wannabe

Rookie

iTrader: (4)

Have you revved up your engine? I believe the single wire alternators need to see about 1500-2000RPM before they start charging.
You have to snap the throttle to get the exciter working.

Others please correct me if I'm wrong.

Chain Runner

if a fuseable link is blown wouldnt i be getting zero voltage though? i could be wrong, im a novice with electrical wiring.

this is a 4 wire alternator, so it should be charging 13.5 volts +/- at idle i believe.

Villian III

After giving the motor a good rev, see if a screwdriver will stick to the bearing cap on the back side of the alternator. If it sticks to it then the alternator is putting out voltage. Then check your battery terminals with a volt meter and post the voltage at idle and at 3000 rpm's. This will help figure out what is going on.

MILD THUNDER

iTrader: (3)

Check to make sure with key on, engine off, you get 12V at the purple wire to the back of the alternator. This is the wire that tells the alt to turn on. Also, when running, check the voltage at the red/purple small wire, which is the sensor wire. This tells the alternator how much to charge.

Chain Runner

thanks guys i will try those couple of things in the next couple days or so.

wannabe

Does this system have the built in regulator or seperate regulator?

Chain Runner

im not sure...i do know that the alternator is found on some merc outboards if that tells you anything?