Boat question

[schmake]

Looking for suggestions on what might be wrong with my boat. I have a brand new battery and only the motor hooked up to it, the other electrical stuff is hooked up to a seperate battery. I can have the battery fully charged and within 12 hours the battery is completely dead, motor will not turn over. Went dead while I was on the lake last week. Anyone with any ideas I would greatly appreciate anything. Thanks

[marine_man]

We could use a little more information.. what size and type of motor? Manufacturer?

If it's a small motor it could be the rectifier... that's what charges the battery on motors that don't have alternators on them like larger 4-strokes. Sometimes a shot rectifier will draw a battery down.

Provide more information first please...

marine_man

[BobT]

Not all outboards with electric start have charging systems or very good ones. If yours does not or if it does but it doesn't work, how often are you using the electric start? I had an older (1987) Evinrude 40hp and it did not recharge my battery. I used a combination starting/deep cycle battery and ran my electric motor, sonar and interior lights and it rarely got low enough not to be able to start my outboard in a day of use. It depended on how much I used my electric or how often I restarted the outboard but I was surprised.

Fortunately, it was real easy to start the outboard with the pull rope so it wasn't a huge concern.

If you really aren't using your battery and yet it loses its charge in about 12 hours, then I'd say your battery is shot or something else is loading your battery (partial short-circuit).

Bob

[Tonka Boy]

I'm guessing your battery is defective. Otherwise you have a short somewhere and it's draining the bat.

[schmake]

Thank you for all of the information. It is a 1994 40 horse Mercury, it does not have a pull start, that I can locate.

[marine_man]

Your motor probably has a charging system of some sort... can you verify if it's working? Using a multimeter measure the voltage of the battery with the motor completely disconnected. Then connect the motor, start it and run it at high idle (in water). Did your voltage reading increase?

If not you've got a charging problem, probably a rectifier... but I'm not familiar with the troubleshooting to verify that...

marine_man

[STEP & 1/2]

It sounds like you have the same problem that I had on my first boat. I had a Johnson 40 hp and it would not charge the bat because of a small rectifier. I was told that Johnson would put in a bigger rectifier for $600.00 way to much for me . What I had to do when on the lake and starting the motor off and on moving around at least once during the day I would have to run around the lake wide open for sometime to charge up the cranking bat this way I was sure of getting off the lake. I also started caring jumper cables with me and when the bat. went dead I would jumper off my trolling bat.

Later on I dumped the boat and motor and picked up a bigger one.

[walleyeaddict]

sounds like a bad batt or a short!!

[Angler Don]

isolate the problem. Charge the battery, leave it complete unhooked from the motor. Does it still lose it's charge? If so, it is a battery failure and it needs to be replaced. If not, then hook it up to motor. Then if it loses it's charge, there is something from the motor draining the battery. Probably a charging system draw. What that draw is depends on the charging system type. Start here and let us know what happens.

Don

[Valv]

Quote:

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I had a Johnson 40 hp and it would not charge the bat because of a small rectifier. I was told that Johnson would put in a bigger rectifier for $600.00 way to much for me .

---

WOW !!! That was a little overpriced, they usually run

from $ 50.00 to $ 100.00

If you are still using same dealer/mechanic I suggest looking elsewhere.....

Anyway I would follow suggestions above, they look pretty much what you should do to start troubleshooting this problem.

[BobT]

I've been told on more than one occasion that those old rectifier type charging systems were not very efficient at recharging a battery. As one post pointed out, you need to run at full throttle for a rather extensive time just to recover from starting the outboard in the first place. Hardly worth the cost of repairing it if you have a good battery with plenty of starting amps and reserve capacity. Too often we settle for the less expensive battery only to find out it isn't adequate for our needs.

Bob