Dead Batteries

[Dubed]

If the starter had an internal short, wouldn't it just be nonfunctional? I have a new starter, maybe I should just swap it out. I like to understand why and not just change parts.
The one place I haven't checked connections is in the 1/2/both switch. I'll definately clean them up before I put the batteries back in

 

[dingbat]

12.6 volts minimum is a full charge ! 12.4 is low but should start the engine, I would check the connections again and why would a new battery just installed, only have 12.35 volts after one start ?? What was battery voltage when installed ? Sounds like a battery with an internal short or a starter with the same.

This happened 3 years ago, then again last Spring. Both times confirmed bad starter though the second time took a bit longer to diagnose due to the “smart charging” feature of the truck.

Armature shorted to ground the first time.
Second time (rebuild) obvious death by corrosion as evidenced by the green fur ball growing out of the side. Replaced with OE MotorCraft this time. Time will tell if this one holds up.

 

[cyclops222]

Check the little battery label on the side of the battery. It is a month / last 2 year digits. Batter should NOT BE OLDER than 6 months.

 

[dingbat]

If the starter had an internal short, wouldn't it just be nonfunctional?

Nope….A dead short typical blows a fuse and shuts them down. A voltage leak, bad brush contact, corrosion, insulation breaks in winding, etc. can induce enough voltage drop to limit performance while at the same time, slowly dripping the life out of your battery.

 

[airshot]

Check the little battery label on the side of the battery. It is a month / last 2 year digits. Batter should NOT BE OLDER than 6 months.

When I buy batteries I won't buy one over two months old and always run a check on it before purchase. If the dealer won't, I go elsewhere.. I have to say, Walley World always does a test when I ask.

 

[Dubed]

Well, it looks like ill be changing the starter then. Is there any way to test it while still on the boat? Im a decent wrench, but electric is definately my weak area.

 

[dubs283]

Voltage drop test, checking resistance values of starting system components

With the battery load testing good the issue is something else. Connections, cables, wiring, component, etc...a dvm with proper use will locate the problem shortly.

Sometimes issues won't be present until after hard load runs so you may be testing on the water after using the boat for a while

 

[Dubed]

I installed a new solenoid this year. New doesnt always mean good.
I understand its really just a bridge to jump the full 12 volts over to the starter when the ignition is activated. Is it possible for the solenoid to be working but not sending the full 12 volts? Maybe I just bought a bad one. (It is an OEM)

 

[dubs283]

Is it possible for the solenoid to be working but not sending the full 12 volts? Maybe I just bought a bad one. (It is an OEM)

Yes

Possible but not probable

If you speculate as to what is causing the issue the whole system is suspect. If you properly test the system the exact cause reveals itself

 

[Dubed]

Yes

Possible but not probable

If you speculate as to what is causing the issue the whole system is suspect. If you properly test the system the exact cause reveals itself

Im not speculating. Its been my experience (mainly with electric/air) that a solenoid either opens and closes, or it doesnt. It was the only thing I changed before this trip. Probably just a coincidence. I'll get in there over the next couple days and do some testing to the best of my ability.

 

[dubs283]

What I quoted from post #28 is the definition of speculation

 

[dingbat]

I'll get in there over the next couple days and do some testing to the best of my ability.

Nothing really to test. As noted earlier, it usually come down to an outright failure

Check ohms between battery and starter. Should be 0. If higher, pull individual cables to test separately.

Check for repeatability of continuity thru the solenoid. Could ohm check through the switch as well

The service manual may give you ohm numbers through the motor, but that means little except to confirm the circuit is in intact.

Really need to tear down for inspection and testing (growler) if you want to confirm the diagnosis. Out right failure is a sure sign

 

[cyclops222]

A bad old starter motor......WILL.....absolutely rundown a battery very quickly.
If it has some shorted copper turns in it. Been there 2 times when poor . I carried a hammer and would tap the starter case in a solid area. Would jar the wearing out very fast BRUSHES enough to make a better current path to move the rotor OFF of the shorted area. If it is just worn brushes ? The battery is not seeing a lot of current demand.
Or the Bendix Clutch and the contacts can become erratic. But a hard to start engine ? Constant weak battery.

 

[Dubed]

Nothing really to test. As noted earlier, it usually come down to an outright failure

Check ohms between battery and starter. Should be 0. If higher, pull individual cables to test separately.

Check for repeatability of continuity thru the solenoid. Could ohm check through the switch as well

The service manual may give you ohm numbers through the motor, but that means little except to confirm the circuit is in intact.

Really need to tear down for inspection and testing (growler) if you want to confirm the diagnosis. Out right failure is a sure sign

Then I guess my course of action will be to check and clean every connection "again" in case I missed something. If it happens again, I'll swap out the starter with the new one I have. Installing a new starter on a 3.7 is a painfull process when the motor is in the boat (but it's do-able).

 

[cyclops222]

How many seconds do you have to crank the motor to get it running....steadily ? Include all restarts for a total time.

 

[Dubed]

How many seconds do you have to crank the motor to get it running....steadily ? Include all restarts for a total time.

Barely touch the key. It fires right up. 1 to 2 seconds. Sometimes need to start a second time if cold and stalls

 

[cyclops222]

Forgot the 1 final test of a starter motor. Before removing it.
Using a set of battery jumper cables. Connect the plus and minus clips FIRST directly to bolts on the motor. Then connect 1of the other ends to the battery. THAT LAST unconnected clip is used as a switch connection. A good motor will start cleanly after you become unafraid of the sparking. A bad SHORTED turns in the motor, will start to eat the metal of that testing clip on the jaw. Might ruin that jaw. But will save a needless motor removal.

You can also do a KEY switch tests of all starter cables by only removing both ends of 1 cable. That will pinpoint if a loose connection is in the PLUS or NEGATIVE circuit cables or contactor.

 

[Dubed]

So, Im "trying" to melt the lead on the jumper cable to prove theres a short??
Sounds a bit sketch.

 

[mike_i]

I haven't read all of the comments so I may be way off or irrelevant or maybe this has already been mentioned. Have you measured the voltage at the starter when you're trying to start the motor?

 

[Dubed]

I haven't read all of the comments so I may be way off or irrelevant or maybe this has already been mentioned. Have you measured the voltage at the starter when you're trying to start the motor?

No. I was out fishing alone. Haven't been able to look at it since. I will be working on it tomorrow. Also never duplicated it that day after swapping batteries