Onan Generator not starting - Help

[kernr]

Good Afternoon -
So while out cruising this past Tuesday morning I wanted to charge up the batteries before going ashore. I went to start the Onan 11.5 KW generator (and nothing but a flashing display from remote at lower helm - it flashed Initializing then off and over and over - no fault codes. The generator made no attempt to start - no noise at all. I then went to engine room and tried to start generator locally - nothing from the control toggle switch and again no noises from the Generator. Both shutdown DC Breakers were in the on position. So we headed for home - end of cruise.

After we got to home port I did the following:
1. Checked genset battery voltage - 12.8 VDC
2. Checked cables on battery were tight - they were
3. Measured voltage of battery cables on left side of Onan - 12.8 VDC
4. Called Onan and got their service manual
5. Followed troubleshooting procedure in service manual.
6. Went into control box on top of genset and disconnected the J4 connector from the P4 connector. J4-1 pin to J4-4 pin read 12.8 VDC
7. Manual said it could be start switch or wiring problem.
8. I checked the continuity of start switch for both start and stop - switch is good
9. Went to remote at lower helm and disconnected to remote switch and panel completely - went to local switch and tried to start - nothing again
10. took both DC breakers off (both replaced with new breakers 2 months ago) - checked continuity on both and both good.
11. Took connector off start switch and checked continuity of start and stop switch again - still good.
12. Re checked battery and terminals - all at 12.8 VDC
13. generator is a 2007 Onan 11.5 KW generator Model MDKBM Spec C

What am I missing here it has got to be something straight forward.

Thanks for any ideas in troubleshooting - appreciated.

Bob

 

[Turtle Blues]

If you are not hearing any noise at the generator: starter solenoid clicking, engaging etc., proceed to the section on checking the starter motor.
You probably want to move the posting to the Power Systems section for increased response.

 

[menzies]

Grab a set of jumper cables and jump across the large posts on the starter relay to make sure the relay isn't bad.

 

[kernr]

Turtle Blues -

Two questions - 1. would't I get a light at starter switch when trying to start if it were the motor or relay? 2. you would think you would get some noise??

Bob

 

[Turtle Blues]

Q1 Yes, didn't notice on your picture that you have the lighted rocker which I believe should light when pressing start

Q2 Usually if you have power you can hear some movement, engaging even if starter motor doesn't turn. Can you get a voltage reading off the starter connection to see if it is being powered by the switch?

 

[kernr]

Turtle Blues -

Well I am not quite sure I understand your question but I did disconnect the J4 connector which is in the control box right behind the start switch (iaw the service manual) and measured from pin J4-1 to J4-4 and got the 12.7 VDC which I believe is correct and supposed to allow power thru to the start switch. The perplexing thing to me is neither start switch starts the generator or even lights up properly.

Bob

 

[oscar]

Hmmmm, is one of the safeties messing with you? Low oil, overheat?

 

[Lepke]

Check the ground connection and battery connections by taking them apart. You can jump the starter solenoid and that should spin the engine but it won't start because of the stop solenoid. If you jump both the stop solenoid and the starter solenoid, then it should start, but you'll have to search out why power isn't getting there by normal means.

 

[kernr]

Oscar -

This possibly is a problem. I looked thru all of the sensors this morning and I do not see any that would prevent starting the generator. There is a low oil pressure sensor but no low oil level sensor. The fact that the remote start button just has all lights flashing and "initialization" flashing along with "establishing communication" is troubling. And locally at start button on genset I do not get the typical amber flashing light while attempting to start. This problem has me stumped and it probably is very basic.

Bob

 

[Turtle Blues]

Does the remote get past "Establishing Communication" or does it freeze at that point?


Is the remote a ribbon connection with a plug onto the board or hard wired?

Thinking if you can unplug it you should have manual control with the unit mounted rockers.

 

[OldDan1943]

What is the battery voltage when trying to start the generator.
Recently, my gen would not start. I gave it 2 tries, about 3 days later, tried again. The battery indicated it was at least 12.5volts, at rest. I could hear the solenoid clicking..... battery was reading less than 11volts when attempting to start the gen. Changed out the battery, started like a champ.
Lesson learned: a 10 year old AGM battery needs to be changed out every now and then.

 

[kernr]

Turtle Blues -

No, the remote display just flashes initialization & establishing communications when you hold down any button on remote. The normal green light that flashes when trying to start stays dark.

There are two connectors under the remote. One is connected and the other is not used - for like a fly bridge display which I do not have. They are identical connectors. Yesterday I disconnected the one connected connector to see if the remote was causing the problem - no change. So I put it back together.

We think alike - nope it had no impact.

I think this morning I will go to boat and loosen, clean and re-tighten all electrical connections from battery to starting motor. The only thing I did between it running for 1.5 hours last Monday evening and not starting on Tuesday at 11 AM was check the oil level and coolant level on genset Tuesday morning.

Since I checked that I have 12.8 VDC at J4 connector I am having trouble believing it is a start motor problem. Yes I know I can jump it but that does not necessarily solve the no starting problem.

Bob

 

[kernr]

OLD Dan 1943 -

I have not watched the battery voltage while attempting to start - probably a good thing to observe. I get no solenoid clicking sounds at all - that is why I did not jump on battery from the start as the problem root cause (no pun intended).

Bob

 

[OldDan1943]

Turtle Blues -

No, the remote display just flashes initialization & establishing communications when you hold down any button on remote. The normal green light that flashes when trying to start stays dark.
Bob

On my Northern Lights gen, there is supposedly a code to that flashing light.

 

[kernr]

Old Dan 1943 -

The code lights are not coming on at all. No codes. You are correct that you can look up the codes if the lights flash - not happening.

Bob

 

[Turtle Blues]

Just to eliminate mechanical questions before focusing on the board I would suggest as others that you put a jumper on the starter to prove that it works and you have sufficient battery power to operate it.

You will also want to test through the safeties and rocker switch under voltage to see if you can establish where the loop is open.

The loss of comm issue if it remains after removing battery power completely for several minutes and then reconnecting is, sorry to say, probably a board issue.

With the remote removed the board should have defaulted to the flash codes and it appears from your description that it did not.

 

[High Wire]

By jumping the solenoid and cranking the engine you prove:
1- The starter motor is good
2- The battery terminal connections to and from the solenoid are good.
3- The battery itself is good.
If the engine cranks then you confirm a control issue and not a high resistance battery connection issue that still gives you good no-load voltage but goes away when a start is attempted.

 

[Xsbank]

The start switch has an over-ride for the oil pressure sensor to allow the engine to crank. The oil pressure-low switch prevents anything from working so try taking that out of the circuit?

 

[kernr]

All -

Results were good on Saturday. The voltage was correct at all points that it should have been. When I lost both start switches I should have immediately gone to the cable / wire connections from the battery to the starting motor (all switch power comes from starting motor) by not only making sure they were tight but taking them apart and cleaning them up as necessary. I knew from the get go it was not a mechanical generator problem because she ran well on Monday evening and you do not lose two starter switches in parallel with each other at the same moment. So yesterday was cleaning day - battery, cable terminals on side of Genset, ground connection to the body of the generator, and positive connection on the solenoid. When I loaded the wires I lost the 12.8 VDC. That was my first solid clue that I had a connection problem. Any way when I had finished cleaning and replaced two green, meaning slightly corroded, connectors - she started right up & purred. Do I know which connection it was - No - but I feel confident in the actions I have taken.

Although on my first pass I made sure that things were tight = that was not good enough. When someone says perform maintenance; it is more than just changing the oil and wiping down a machine - inspect carefully.

Thank you to all those with ideas on what could possibly be the root cause - it really helps to brain storm problems like this one where the service manual states - get a service tech from Onan - Not happening!! I keep learning about this new boat, to me, and she is a beauty.

Bob