I took the boat out today and the 115 main motor would not turn over, but the 9.9 would.
I cleaned the terminals really good as they were cruddy bad corroded.
I turned on the lowrance and the voltage showed 6.8 volts and the marine radio showed low battery but it doesn't give you the voltage, it is wired with 10 gauge wire.
I had the boat out a week or so ago and it started fine.
Could the battery terminals have been dirty enough so the battery wasn't getting charged when the main motor was running ? Could the battery have crapped out that quick ?

I would appreciate any help or advice anyone could give me.

I took the boat out today and the 115 main motor would not turn over, but the 9.9 would.
I cleaned the terminals really good as they were cruddy bad corroded.
I turned on the lowrance and the voltage showed 6.8 volts and the marine radio showed low battery but it doesn't give you the voltage, it is wired with 10 gauge wire.
I had the boat out a week or so ago and it started fine.
Could the battery terminals have been dirty enough so the battery wasn't getting charged when the main motor was running ? Could the battery have crapped out that quick ?

I would appreciate any help or advice anyone could give me.

Bob,
In the last couple of years, I've had batteries die (lose cells) while parked for 15 minutes. Throw it on a battery charger, but I'll bet it's a goner.
HRG

Yep, batteries shed lead over time that end up in the bottom of the cell cavity, then they can short/bridge that cell.
Check water level, place the old battery on a charger, once charged check gravity, maybe even a load test.
Start the outboard and make sure you are seeing around 14v at the battery to verify the outboard is charging.

Yep, batteries shed lead over time that end up in the bottom of the cell cavity, then they can short/bridge that cell.
Check water level, place the old battery on a charger, once charged check gravity, maybe even a load test.
Start the outboard and make sure you are seeing around 14v at the battery to verify the outboard is charging.

How do I hook up a volt meter to test voltage at the battery to see if the motor is charging ?

I do not remember exactly how old the battery is so I would say atleast 3 or 4 years old.

Which is needed for a starting battery with a 115 Merc, a group 24 or 27 ? I have my Lowrance and marine radio hooked up to it, as well as power for lights, livewell pumps etc from the factory.

Rebs.
Try the following:
1. Remove all wires from your battery, one terminal at a time.
Have a bottle of baking soda solution and a tooth brush and really scrub each of the wires to insure that you have removed all of the corrosion.
Then, use a battery terminal cleaner to insure that the terminal itself is completely clean.

2. Repeat for the other battery terminal after you have reconnected all of the wires to the first terminal.

3. Check the water levels in the battery - if you have caps on your battery and insure that the water level is above the plates.

4. Put the battery on charge for 24 hours to be sure that you have had the batteries in place long enough to fully charge a "good" battery.
If, at the end of the 24 hours and put a meter on the battery, you should be reading a voltage that is close to 14 volts.

5. Now, if you feel good enough to be able to start the motor, you can use your muffs to stop and start your motor a few times.

If you start the motor a few times, but don't let it run much in between times, you would expect that the surface charge would be bled off of the battery and a voltmeter check on the battery - with the motor shut off - should read a voltage that is between 12 and 13 volts.

6. Now, go ahead and start your motor. As you are starting your motor and cranking it over, the voltmeter should be reading a voltage that is above 11 volts.

7. Now, let the motor run on muffs in the driveway at about 1/4 throttle or 3000 rpm for about 10 minutes.
Now check the voltage on the battery with the motor still running at about 1/4 throttle.
If the alternator on the motor is working correctly, you should be seeing something that is over 13 volts.

Note:
You may have a good alternator - but a bad battery. If after the overnight charge, you don't get good vigorous spinning of the engine over when you attempt to start the motor, you likely have a bad battery.
So, if you continue testing with this motor that is likely defective, you may never get the voltage over 10 or 11 volts and mistakingly blame the alternator.
So, to be 100% sure, after charging the battery for 24 hours, you might take the boat to a battery store that does load testing. Have the store test the battery to see if it is up to Snuff or not. If it isn't then buy a new battery and charge it for a few hours. Then, repeat the motor test to see if the alternator adds at least 1 volt to the battery as soon as the motor starts. This would indicate that the alternator is working fine.
i.e. as soon as you start the engine and have it about 1/3rd throttle or above, you should see a noticeable rise in the voltage that is present on the battery terminals.

Take care
REW

I just went out and checked the battery and sure enough the water level was low some and plates were showing. I guess this battery is done, right ?

go get an Optima gel battery. and be free of issues for I'll bet 5 years or more.

here's a link

http://www.optimabatteries.com/marine/

pricey...but they rock and can take a beating!

go ahead and place some distilled or deionized water into it just above the plates and charge it.
You can always replace it, although you may still get a season or two out of it

If you get a gel battery, make sure your charger supports them as normal wet cell battery chargers do not
You need one that has a charge profile for Gel or you will limit the life of them

worth a shot, keep water level at least 1/4 inch below top because you do not want boil over.

I thought water level checking in batteries was a thing of the past. I figured all were sealed units.

I would go with the group 27. Bigger is better.

Rebs,
Not necessarily at all.
Just be aware, that when a battery charges, water is pushed out of the cells and is indicated by rising water levels in the battery.
When a battery is discharged, the water level falls, as the electrolyte is sucked into the cell material.

So, in your case, add just enough water to be sure that all of the plates are covered.

Then, put the battery on a 24 hour charge.
Now, recheck the water level and bring the water level up to the full water level as indicated by the change in neck hole size in the battery fill hole.

Then, take the battery in for a load check to determine if the battery is bad or good.

The idea is that you Don't want to fill a battery to the fill level, if it is discharged. If you do, and if the battery takes a charge, the cells will be overfull, when the battery is fully charged.

Fill the battery so that all of the plates are just covered for any cells that have levels lower than that. Then, fully charge the battery and THEN, top the water levels to the correct level.

Be safe
REW

Thank you guys foir all the help. The battery is done, it had been on charge for almost 24 hours and it did not charge at all. Now I have to decide what battery to buy, another walmart everstart or a sealed battery, agm or jel. I am thinking about the Sears die hard sealed with a full 3 year replacement warantee, but they are costly, about 240.00.
What would you guys recommend ?

I like the Interstate 27M-XHD http://www.interstatebatteries.com/cs_eStore/content/product_info/marine_f.asp paid about $105 at Gander Mountain early last year.
That Sears AGM is a BEAST, if you do go that way, make sure you have the room for it. Just looking at it on the shelf, it appears pretty large.
HRG

Just be aware that wet cell sealed batteries do have an outlet for the gassing that takes place.
Therefore the water levels CAN drop, and then there is no way to re-fill them.

Them wal-mart batteries are hard to beat for the cost.

Rebs,
Go to Walmart and get a deep cycle group 27 batteries for $70 and don't look back.

This battery will likely last you 5 years and if not, pick up another one.

Really no reason at all to spend much more than $70 or $80 for a decent battery.

Or,
Go to batteries plug and get a group 29 or 31 for nice long fishing time at night with no motor running.

http://www.batteriesplus.com/product_search/33868-Group-31-Marine-and-Boat-Deep-Cycle-Battery-DASH--DASH-Xtreme-SLI31MDC.aspx


Good fishing.
REW

I like the Interstate 27M-XHD http://www.interstatebatteries.com/cs_eStore/content/product_info/marine_f.asp paid about $105 at Gander Mountain early last year.
That Sears AGM is a BEAST, if you do go that way, make sure you have the room for it. Just looking at it on the shelf, it appears pretty large.
HRG

our local Gander only has the group 24 XHD with 800 cca, 1000mca and 135 rc@25 amps
The 27 XHD has 180 rc@25 amps, 800 cca, and 1000 mca
would the 24 be enough battery ?

what does the RC@25 amps actually mean and how important is the extra 35 minutes on the group 27 ?

Bob:

Your motor owners manual should specify the required minimum battery size in MCA or CCA. The Group 24 and 27 batteries you described are identical in this spec and either is probably adequate. The RC tells you how many minutes it takes to fully discharge the battery at a constant 25 amp load. For a starting battery, RC is almost irrelevant. RC only matters if you also run accessories off the starting battery when the main motor is not running.

I went to walmart and looked at the ever start group 27. On the battery it says 700 MCA and 115 hrs @ 1 amp. When the guy there tested the brand new battery for MCA and it showed 883 MCA
what does all that mean ?