1988 Johnson 50 charging problem

[Trollstriper]

Looking for some help with my 1988 Johnson 50hp model # (J50TLCCS) not charging. To give you some idea of how i use the motor, we troll for striper at idle for hours, occasionally at wot from place to place, but mostly idle. The only load on the battery is a lowrance hds 7 with structure scan ,and it does have tilt and trim thus killing the battery that much quicker if i use it. In this situation the battery will last about 2/3 of the day and then wont turn motor over. i have done alot of searching on this forum reading different threads and done the Joe Reeves rectifier test which seem to pass so i dont know where to go from here. I also checked the voltage at battery, alone 12.50 volts, hooked up at idle never above 12.84 volts and 3000 rpm 13.00 volts. Checked for loose or broken wire found nothing. thinking maybe stator but dont know where to start to test it. any help would be appreciated. Thanks.

 

[Larry3215]

Re: 1988 Johnson 50 charging problem

Sounds like your charging circuit is woprking as its supposed to.

The problem is the charging circuit doesnt put out much power - especially at idle. I dont know for sure on your model, but my 70 only puts out 6 amps max at 5500 rpm. At idle its next to nothing. Even at full throttle, its going to take hours to recharge a dead battery at that rate of charge.

I use a kicker for trolling, so I dont have the same issue you have, but I still make sure the batt is fully charged before every trip out - I keep it on a battery maintainer all the time when its parked. I am also using the largest battery that will fit the space.

You might consider going to a larger battery or even a dual set up where one is used only for starting and the other is used to run the electronics.

 

[Will Bark]

Re: 1988 Johnson 50 charging problem

Or if you are going to two bat setup you can hook po to pos and neg to neg and double the capacity of the 12 volt system. I would also have the present bat load tested to see if it is really getting a full capacity charge and holding it. Good luck

 

[Trollstriper]

Re: 1988 Johnson 50 charging problem

[ I would also have the present bat load tested to see if it is really getting a full capacity charge and holding it. Good luck[/QUOTE]

i did have the battery load tested at local auto parts store and tested ok. i guess the thing that gets me is , my friend that i fish with has about the same setup except his motor is a 1984 classic 50 mercury and when we use his boat (which has been alot lately) due to my problems it does not have this problem. it is just fustrating carrying extra batteries and charger on 2 and 3 day trips. is there nothing i can do to get better charging. ive owned several boats and never had this problem before.

 

[Joe Reeves]

Re: 1988 Johnson 50 charging problem

i did have the battery load tested at local auto parts store and tested ok.

If that store test was one of those "state of the art" put the battery on charge, then do a load test... that proves absolutely nothing. That test is a joke which will not show up a bad cell in any battery. More than once I've taken a battery in to be replaced under warranty that I know for sure had a dead cell and that test would indicate a good battery.

On such an occasion (more than once over the years), after being told the battery was okay, I'd insist that they double check the battery cells individually with a hydrometer. They always put up a mild argument and on one occasion I had to go get my own hydrometer to prove my point. The hydrometer showed up the bad cell when their state of the art equipment would not. (Mechanic vs Sales Personnel).

If you don't have a hydrometer, buy one (they're cheap) and check that battery yourself.

 

[ondarvr]

Re: 1988 Johnson 50 charging problem

Even with no charging system it should last longer than that. If you run at higher RPMs for a while does the voltage go any higher? If the battery is fully charged the voltage may climb to around 17 volts when running on plane.

 

[Trollstriper]

Re: 1988 Johnson 50 charging problem

If you don't have a hydrometer, buy one (they're cheap) and check that battery yourself

Will do. Let you know how it turns out. thanks.

 

[Trollstriper]

Re: 1988 Johnson 50 charging problem

. If you run at higher RPMs for a while does the voltage go any higher? If the battery is fully charged the voltage may climb to around 17 volts when running on plane.

I will check at wot throttle next trip to lake ,right now boat is tore down getting face lift.new carpet and such. thought this to be good time to trouble shoot problem. Thanks for everyones help. i hope to get this solved.

 

[boobie]

Re: 1988 Johnson 50 charging problem

The only proper way to load test a battery is to have a tester that has a carbon pile and volt/amp meter in it.

 

[JRDIII]

Re: 1988 Johnson 50 charging problem

Make sure all of your electronics are grounded properly. That was the problem with the '92 Johnson 40hp that came with the boat I purchased last summer. I found that the light on the compass was not grounded correctly. Somehow, that little wire was preventing my battery from recharging. When I replaced the compass with a tachometer that uses the wiring harness that plugs into the Johnson control, voila, it started charging.

 

[Trollstriper]

Re: 1988 Johnson 50 charging problem

Make sure all of your electronics are grounded properly. That was the problem with the '92 Johnson 40hp that came with the boat I purchased last summer. I found that the light on the compass was not grounded correctly. Somehow, that little wire was preventing my battery from recharging. .

That is interesting. in doing the facelift on my boat, removed console and there are cut wires inside. one i can think of right off is in the tilt/trim harness a brown or black i have to look to be sure and i think also one or two on the switch. a small red light on dash panel cut out and what i assume to be some type of alarm buzzer on the motor harness is not working( full of rust). i did get a repair manual ordered but im not sure what all that is going to show me but i'm certian with the knowledge in this forum we'll get it figured out. i also removed speedo which wasn't working but only light was wired on it, just took it out of the loop of other gauges. thanks for the input that will give me another path to follow. i'll go to the shop in a little while and check the wires and try to get them posted today. the battery is also being tested by my cousin (skilled auto mechanic for many years) like joe said, maybe get the results of that today. thanks again everyone!

 

[Larry3215]

Re: 1988 Johnson 50 charging problem

I doubt if your problem is a simple loose wire. The numbers you posted above show that your charging system IS working. Thats not the problem.

Its a matter of too little power in vrs too much power out.

You run at idle for 5 or 6 hours at a time. You can see from the test you did above that your charging system puts out very little power at idle. ALL charging systems work that way. Its the nature of the beast and no way around it.

So, lets say your Lowrance draws maybe 10 amps while its running. 10 amps for 6 hours going out of your battery. Then you run at full throttle for a few minutes. At full throttle your charging system only puts out at MAX maybe 6 amps - and thats assuming its working as good as new.

So you've got 10 amps x 6 hours = 60 amp/hours going out and maybe 6 amps x .1 hours = .6 amp/hours going in. Even if you ran at full throttle for a whole hour your still not even close to replacing the amp/hours you have used up.

You would need to run at full throttle for 10 hours to recharge that battery completely.

Its simple math and unfortunately, its working against you based on how you operate the boat.

If your batteries capacity is down due to age or what ever, that just makes it worse.

Your only solution is to increase your existing battery capacity so that you can run all day without killing the battery.

 

[ondarvr]

Re: 1988 Johnson 50 charging problem

It uses 0.7 amps. I had the same motor and trolled all day, day after day and never had a problem with my battery going dead.

 

[Trollstriper]

Re: 1988 Johnson 50 charging problem

If that store test was one of those "state of the art" put the battery on charge, then do a load test... that proves absolutely nothing. That test is a joke which will not show up a bad cell in any battery. More than once I've taken a battery in to be replaced under warranty that I know for sure had a dead cell and that test would indicate a good battery.

On such an occasion (more than once over the years), after being told the battery was okay, I'd insist that they double check the battery cells individually with a hydrometer. They always put up a mild argument and on one occasion I had to go get my own hydrometer to prove my point. The hydrometer showed up the bad cell when their state of the art equipment would not. (Mechanic vs Sales Personnel).

If you don't have a hydrometer, buy one (they're cheap) and check that battery yourself.

You were right joe. my cousin as i mentioned (auto mechanic) took battery and done his testing on the battery checking amperage instead of voltage . charged to 100% let it set few hours charge to 100% again and left to set over night. return in the morning checking battery, had pulled itself down to 80%. loaded it for seven seconds and drop like a stone to 68% and stabilized at 70 %. at full charge suppose to be 625 cranking amps only done 400 amps. Checked with hydrometer and one cell down. had ruled out battery due to the auto parts store. will check my own batteries from now on. Thanks for the help.

 

[Joe Reeves]

Re: 1988 Johnson 50 charging problem

Glad to hear that you found the problem and that my version of that so called "State Of The Art" battery tester was listened to. The hydrometer really is the better of the two testers.... and it sounds like your cousin knows exactly what he's doing. I'd like to be a fly on the wall to listen in when you return to that auto parts store.

Understand that I'm not knocking any auto parts store as I myself do obtain valuable advice from them in many areas from time to time... it's just that they have been trained and brainwashed into believing the hype that goes along with that battery test equipment which actually causes customers to have their problem prolonged.