Battery dying quickly

[ssmetana]

I have a 60hp 1989 'rude. When I crank to start, I get 3-4 attempts for the engine to fire before cranking power starts to drop off to the point where it cannot turn the starter. It appears that the battery is bad but this is the second one and the first one checked out fine in full load test at the store. I have also had two instances where I had run the motor for 2-3 hours, turn the key off, and tried to restart but it ws dead. Not sure if these are tied together. I'm trying to rule out things as much as find the problem. Can I assume starter and starter solenoid are good, based on the fact I get 3-4 good start attempts? I'm leaning toward bad battery or faulty wiring or ignition switch but not sure. Any thoughts from anyone?

 

[knehdn]

Re: Battery dying quickly

Here's a couple of quick tests which don't need a meter... 1. See if the positive terminal has risen or started to push the plastic casing up. 2. Give the battery a squeeze from both ends. Feel at first if it's soft enough to push or not. If it's hard and you can't push in, the plates have swollen (which is why the positive has risen), are sulfated, and thus making the battery history.

 

[Vic.S]

Re: Battery dying quickly

Can I assume starter and starter solenoid are good, based on the fact I get 3-4 good start attempts

I would assume that too. I would also assume that the wiring is good.

But it would be well worth while checking all the connections in the wiring, not forgetting the negative ground connection.

It would be worth feeling for any warm connections after several staring attempts ... that would indicate a bad connection.

I would do some voltage checks . Measure the volts directly at the battery terminals while you are cranking and also at the starter motor. If the volts at the battery fall way off below say 10 then the battery is the culprit. If the volts remain fairly good at the battery but fall at the starter motor then there is problem with the wiring.


Are you sure your battery is fully charged. It shows the symptoms of not being so.

Take it off the boat and charge it ... see if that makes any difference.

Have you checked that it is charging on the boat. It should not be dead after several hours running

You have a non regulated rectifier. If it is charging you should see the volts rise to well above 12 volts ... up to about 14.4 when the battery is charged but because it is unregulated then go on rising to 16volts maybe more.

Do you have an adequately large capacity battery?
Is it a starter battery .. not a deep cycle one?

Check the battery volts when it has stood idle with no charging and no load for 12 hours or so.
If it is good and fully charged you should get 12.7 preferably 12.8.
At only half charge you'll get around 12.2 volts
Anything below 11.8 is almost fully discharged.

 

[ssmetana]

Re: Battery dying quickly

Vic S.

When the motor is running, should I check the voltage at the battery terminal posts, and it is here I should see the 14-16 volt reading? If I do not see that, then are you suggesting the rectifier is bad?

 

[Vic.S]

Re: Battery dying quickly

Yes at the battery posts but you should see the same at the red lead from the rectifier.

If you do not see that then the rectifier could be bad. Less likely but it could be a defective stator coil.

Rectifiers will be instantly fried if the battery is connected with the polarity reversed ... ring any bells? It may also be damaged if the battery is disconnected while the motor is actually running.

On the Engine FAQs board you will find instructions by Joe Reeves for testing the simple round rectifiers. If you try that and use a digital multimeter use it on the diode test range because they do not all work on all the ohms ranges for diode testing.

 

[ssmetana]

Re: Battery dying quickly

Vic S.

Is there a quick way to locate Reeves post. I'm fairly new to the sight and with so many posts, I'm not schooled on the short cut tools available to locate specific items.

Thanks

 

[knehdn]

Re: Battery dying quickly

You could use an anolog meter if need be. Place one lead on the tail and one on the stud, then notice the swing (if any) of the meter... and then reverse the leads. If the meter only swings one way, it's OK (or at least should be). If it swings on both tests, it's blown closed and needs replacing. If it doesn't swing at all, it's blown open, and again, needs replacing. Just my $0.02.

 

[Vic.S]

Re: Battery dying quickly

Is there a quick way to locate Reeves post.

You have failed the initiative test.
Go to the "Repair and maintenace index". The Engine FAQs board is the top one in there. Scan down the titles and it's about half way down the first page.

But you could cheat and click THIS LINK

As said an analog meter will do the job no probs. Its just that digital meters work with such low voltages they cannot be relied upon to test diodes on the ohms ranges, hence the recommendation to use n the diode test range. If no diode test range use the highest ohms range but be suspicious if it shows all the diodes open circuited

 

[ssmetana]

Re: Battery dying quickly

Vic S.

I got home and put the meter across the battery. It read 13.5V. I turned the key, the starter struggled, and the battery reading dropped to 8.6V. So, does it sound like a bad battery or else?

 

[Vic.S]

Re: Battery dying quickly

8.6 volts would suggest to me that the battery is defective or significantly discharged.
You did take the reading directly from the battery posts though, not from the connectors, otherwise the low reading could be due to bad connections onto the posts.

13.5 initial reading is high. that suggests you had the battery on charge just before. ??

Sensible to get the battery properly load tested.

When sorted check that you engine is charging properly.

Also remember that you should never leave a battery in a discharged or even partly discharged state. The charging output from your engine is not great, nothing like the output from a vehicle alternator for example, so it would be easy to drain more from the battery, if you have much electrical equipment in use on the boat, than the engine can replace. That would mean you would need to remove the battery and recharge it regularly or fit some additional charging eg a solar panel

 

[kenmyfam]

Re: Battery dying quickly

Have we verified that the cables and connections are actually good ??? or do they "Look O.K."

 

[ssmetana]

Re: Battery dying quickly

I did not just take the battery off charge, it has been off charge for a week, and still read 13.5V on the posts and dropped to 8.6V when I turned the key.

I think I'll start with a new battery as it looks like in any case, this should be upgraded. We'll see how it goes from there before suspecting solenoid or starter as being the problem. Then, once I get it out running, I'll start the "draining after long hours running" issue to see if or what is causing it.

Thanks for all your input.

 

[wilde1j]

Re: Battery dying quickly

Start by having battery load tested. Most auto parts stores will do this free. Then carefully inspect all heavy battery cables, including the ground cable. All connections should be bright and tight, wire free of corrosion.

 

[wilde1j]

Re: Battery dying quickly

Vic S.

I got home and put the meter across the battery. It read 13.5V. I turned the key, the starter struggled, and the battery reading dropped to 8.6V. So, does it sound like a bad battery or else?

If it read 13.5 volts with engine running, that's fine. If not running, get another meter. Low reading when cranking suggests any ar more than one of the following 1) bad cable(s), 2) bad termination(s) 3) bad solenoid or 4) bad starter.

Have you eliminated the solenoid by jumpering around it with a heavy jumper?