Small Engine Troubleshooting Problems? Ask a Mechanic Now.
What is the full model number of the genset?
Sorry, I work 2 jobs, and help on Just Answer in the evenings. I am not ignoring youi, I just can't be online 24/7.
I am on Eastern time.
The most common cause of your issue is that the genset is no longer producing power.
Connect an AC voltmeter to the output leads of the genset.
Press and hold the stat button to keep the genset running for 5 or 6 seconds.
What voltage reading do you get?
The output leads are the 120V lines coming out the left side of the genset. They are in a gray conduit.
No, the engine will not run if the genend is not producing power. This is a safety feature to prevent further damage.
If your coach has a transfer switch, you will not be able to use a receptacle to check for power. You need to check ti directly at the genset.
Don't take it apart at the genset - it is impossible to get it back together without taking the genset out of the coach.
It is normally easier to open the conduit from the other end, as the conduit leads to a junction box.
If you have one of the oddball j-boxes that is just too hard to get to, you will need to remove the control panel from the genset to access the back of the circuti breaker.
The chassis engine may or may not charge the house battery. It depends on how the coach is wired.
Most gensets are connected to house battery, but sometimes I see them on the chassis battery. I can't say how yours is without seeing it.
Remove the access cover from the genset.Inside, you will see a ‘divider’ about 2/3 the way to the left.Attached to, and going through, this divider, are 2 white plugs.The plug on the bottom is a 15-pin plug and is for the controller. The plug on top is a 12-pin plug, and is for the voltage regulator.
Disconnect the 12-pin voltage regulator plug. On the right side of the plug (the side leading back to the generator), locate the wires marked J4-9 and J4-10.Set your meter to ohms and connect one lead to each of these wires. It should read about 18 ohms.Now reconnect the plug and set your meter to VDC.Connect the negative lead to a good ground, and back probe the positive lead into the plug at wire J4-7.Press and hold ‘Start’ for about 5 seconds. It should read at least 10V.Now back probe the positive lead into the plug at wire J4-9 and press ‘Start’ for about 5 seconds. It should read a minimum of 12V, and preferably between 20-30 volts.Now back probe the positive lead into the plug at wire J4-10, and press and hold ‘Start’ for about 5 seconds. It can read anywhere from 1-30 volts, as long as there is a reading.
What do you get with these tests?.
Yes, a bad voltage regulator.
Part number of VR is(###) ###-#### Don't know the cost.
Do NOT run the genset without the maintenance door. It will over heat and burn up.
Part number of door is(###) ###-####
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You only gave partial results.
If you are still getting 27 ohms across P4-9 and P4-10, your brushes are fine.
There is no oil shut off on this unit.
You may need to test the stator.
It is somewhat unusual for them to go out, but when they do, they tend to take the voltage regulator and rotor out with them.
The genset needs to come out of the coach and the top cover removed to test a stator.
The rotor is good, or you wouldn't have gotten 27 ohms across the brushes.
Click here to download the stator test.
I am not going to be able to continue with this issue much longer. It is already past the point where it just isn't worth my time.
It never hurts to change a fuel filter, but is usually unnecessary.
You do not have to remove the filter alone, but it is attached to the fuel pump, and you do have to remove the pump.,
Yes, those are the pages from the service manual.
You can order one through any Onan dealer. The part number for the one you need is(###) ###-####
Some people do get a portable, but they are a major hassle. You have to carry the genset, as well as the fuel. Then you have to load an unload the genset wherever you go.
The old saying "you get what you pay for" REALLY counts when buying a genset. If you do decide to go with a portable, stick to a brand name unit. Don't get chincy on a Chinese unit.