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Ask Hank F. Your Own Question
Hank F.
Hank F., RV tech - emphasis on gensets
Category: RV
Satisfied Customers: 14487
Experience:  RV tech since the beginning of the millenium.
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I have an Onan 4000 Microquiet gas generator. While doing my

Customer Question

I have an Onan 4000 Microquiet gas generator. While doing my monthly run time it stopped by itself. I could not get it to crank over again; it just clicks and makes a buzzing sound. I reconnected to the coach to the land power and was running the A/C and the main circuit breaker then popped after 5 min. The breaker kept doing this. I disconnected the +\- cables from the generator to separate it from the coach and the main breaker no longer tripped. Reconnected the generator and breaker trips. This leads me to the conclusion that there is a short in one of the generator components. Maybe the starter or solenoid? Any thoughts? Thank you
Submitted: 1 year ago.
Category: RV
Expert:  Hank F. replied 1 year ago.

Hello, thank you for requesting me.

I need you to recheck your model number. The spec 26100A is not a microprocessor controlled unit, and does not show fault codes.

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What is the serial number of the genset?

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Customer: replied 1 year ago.
E060925780. I took the solenoid out today and bench tested and it was bad so I order one on eBay. Let me know if you have a different thought. Thanks
Expert:  Hank F. replied 1 year ago.

I can't have a thought without more information - such as which model it is, what you "hooked up" on the genset, etc.

But a starter solenoid will not affect an AC system at all.

Customer: replied 1 year ago.
The generator was affecting the coach. Disconnecting it from the coach solved the main breaker problem on the coach service panel since everything works fine connected to the shroreline. The s/n is in the previous post. The model # ***** *****
Expert:  Hank F. replied 1 year ago.

Spec 26100K makes all thedifference in the world. It is a completely different unit than a 26100A.

When you say "Disconnecting it from the coach solved the main breaker problem on the coach service panel since everything works fine connected to the shroreline.", I assume you are saying that you disconnected the 120V wiring from the coach? Not the 12V remote wiring? Or were you referring to the main battery cables? (This is the kind of detail I need).

Exactly how did you have the 120V connected to the coach? Did you have it tied directly into the main breaker box? Did you have it through a transfer switch? Did it go to an onboard receptacle that you need to plug your shore cord into?

Was this buzzing sound coming from the genset, or some other part of the coach?

Remember, I can not see or hear what is going on. I only know as much as you tell me.

Customer: replied 1 year ago.
I disconnected all wires from the genst to the coach. When I did that and have the 120v shoreline plugged in I can run everything in the coach (A/C, micro, lights, etc) without tripping the breaker. The click and buzzing was when I tried starting the genset and was coming from the genset. Sounded like it came from the starter relay so I took that pit and bench tested it and ther was no action of the magnetic plates connecting. So I ordered a new start relay.
Expert:  Hank F. replied 1 year ago.

Ok. I understan about the start solenoid.

But the starting system of the genset has nothing to do with tripping breakers in your coach. The starting system is 12V, and the breakers are 120V.

Customer: replied 1 year ago.
I don't understand either. But if the start solenoid is shorting out and connected to the coach could that trip the main breaker?
Expert:  Hank F. replied 1 year ago.

As I stated in my last reply, no. The solenoid is part of a 12V system. The breakers are part of the 120V system. The 2 systems are not interconnected in any way. At least they are not supposed to be.

Customer: replied 1 year ago.
I agree, but there must be something in the genset system that could cause a draw on the coach 120v system. When the genset is not running and connected to the coach, the main breaker trips with a moderate load. When I disconnect the ground wire from the genset chassis I can run the A/C and the microwave without tripping the main breaker. What is your suggestion on what it could be or where to start checking?Thanks
Expert:  Hank F. replied 1 year ago.

Please scroll back up to my reply of 23 Sep, 9:22PM.

What about the rest of that information that I requested?

Customer: replied 1 year ago.
Can you repeat what information you need?
Expert:  Hank F. replied 1 year ago.

Exactly how did you have the 120V connected to the coach? Did you have it tied directly into the main breaker box? Did you have it through a transfer switch? Did it go to an onboard receptacle that you need to plug your shore cord into?