Genset cranks up at 14.5v but not at 13v

[colonel]

The genset was properly diagnosed by a proffessional mechanic and his conclusion is that it ceased. Where exactly and why is not known yet.

Mechanic removed starter and tried to rotate manually - it wont turn.

[a64pilot]

Originally Posted by colonel

I've tried to remove the starter and jump start it - it spins fine.

So between then and now the starter has seized?
No matter, so long as you can get it fixed. If you have to buy a new one, I’d look into getting the seized one overhauled so you have a spare.

[Miniyot]

My first reply had to do with the starter solenoid. Now the OP comes back and says the starter is seized, yet it would work when hooked up to shore power.

I wonder if his shore power has a battery charger hooked up to charge his batteries? If so, then he probably has a dead cell in his genset battery.
If this is true, then his mechanic is padding his bill by saying it is a bad starter, or isn't that good of a mechanic, or the OP is trolling.

Think about it. The OP said the genset would only start when he was on shorepower. When not on shore power The battery voltage would drop to 10V. and not crank. I wonder what the voltage was without trying to start the genset without shore power hooked up? We never heard that.

[Nineteen]

Hi
If it was installed with the supplied starter cables - unless and even if your battery is mounted directly with the genset, they really are on the small side.

I am fitting one of their Whisperpower 5kva units to our Catalina 380 and will be upgrading the cables. The voltage drop will bee too hard on the starter and reliability.

Cheers
Tom

[Dave9111]

Although he may have found a bad starter, its common for problems like this to be due to multiple issues.


1. Load test the battery - its generally free at Autozone, etc.
2. If the cables are getting hot (you can't hold it in your hand) after a quick crank, you have cable/connector issues. If its only slightly warm, move on. (Ground connections are as important as the battery connection).

If sparks blow out from the connections, yes, you guessed it, you have a bad connection. Tighten, clean, repair, or replace.

3. Starters that get hot or throw sparks after a moderate crank - are in general living on the edge or they are simply bad. Replace/repair.



And yes, if your system is corroded and old, you can have all of the above.
In general I inspect the battery and load test it (easiest).
Monitor the cables and replace as needed.
Start swapping hard parts - like the starter.


A hard crank on battery in good condition shouldn't pull the voltage at the battery much below 11.5 volts. Note that this is when the starter is actually rotating and cranking the engine. If the engine won't crank, try turning it by hand. If you can't, the starter won't either.



And yes, I'm a EE.


But they didn't teach us this stuff in college.



Dave

[jimbunyard]

Originally Posted by colonel

The genset was properly diagnosed by a proffessional mechanic and his conclusion is that it ceased. Where exactly and why is not known yet.

Mechanic removed starter and tried to rotate manually - it wont turn.

Sounds fishy to me.

Do you mean the engine has seized (ceased)? Certainly possible, but the fact that it started and ran 'normally' before would have me scratching my head.

To field test a starter, you hook it up to a battery and see how it spins. If the starter is a planetary gear reduction starter, you may not be able to turn the armature by turning the drive gear, depending on the design.

Don't want to dis your mechanic, but 'professional' only means that he's paid for his work...

[aboon]

I’m late to this discussion but had a similar problem recently. Engine would not turn over with the starter battery and (usually) started reluctantly with engine and house batteries paralleled. I borrowed a clamp-on ammeter and put it around the positive lead to the contactor, with ‘peak hold’ on. The reading was over 800 A, for a starter motor rated at 2.3 kW.
The IR of the starter motor was effectively zero. Replaced the starter motor and all is now good.
I highly recommend a clamp-on ammeter (1000 A range). It took a lot of guesswork out of the process.

Andrew

[Oasis51]

Does this genset have glow plugs and is there a faulty one that is shorted?

[Buzzman]

It's not a bad starter, it's a seized engine. He said so. The mechanic tried to turn it by hand and it won't turn.

When the starter is disconnected it spins fine. He said so.

He's now diagnosed the problem. Seized engine. Massive load on starter. End of story. Rebuild genset diesel.