A New Generation
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A New Generation
A New Generation
When your motorhome’s generator finally calls it quits, installing a factory replacement is usually the best solution
By Chris Hemer / Photos by the author
T

hink about the last time there was a power outage in your area — and the number of times you inadvertently flipped a switch, expecting the light to go on. After the third or fourth time, you likely chuckled to yourself, feeling silly for not remembering that the situation has not changed.

This is how dependent we have become on good, reliable power — we take for granted that it will always be there. In our homes, we usually don’t have to suffer without power for too long before the local utility company comes to the rescue, but if you’re boondocking in an RV and the power goes out, it’s a different story. A non-functioning AC generator can mean anything from an inconvenience to a potentially life-threatening situation.

A generator’s reason for being is to run frequently under load to create 120-volt AC power for appliances like the air-conditioner, microwave, hair dryer and coffee maker. Its enemy is dormancy; to sit unused for months at a time can create numerous problems, from hard starting and rough running to not starting at all. That’s why most generator service professionals recommend that a generator be run at least once a month under load for half an hour or more to make sure it can be relied upon for your next trip.

This Onan MicroQuiet 4000 generator had 1,456 hours on it, or roughly half of its normal life expectancy
This Onan MicroQuiet 4000 generator had 1,456 hours on it, or roughly half of its normal life expectancy. Years of neglect finally took its toll, however, rendering the unit inoperable and unrepairable.
Replacement generators are readily available through Cummins-Onan
Replacement generators are readily available through Cummins-Onan. This tag, located on every Onan/CumminsOnan generator, will tell the company everything it needs to know to provide you with the correct model. In this case, the original gasoline-powered MicroQuiet 4000 would be replaced with an Onan QG 4000 generator.

Quite apart from the costs and time involved with generator repair, at some point the generator may cease to function altogether — at which point it may no longer be worth the investment to repair it. While a gummed-up carburetor can be rebuilt or replaced for a few hundred dollars, a bad rotor and stator assembly can cost $1,000 or more — and these expenses don’t include labor. If the generator in question has still got a lot of service life left in it, a re-build may still be a cost-effective solution, but if the unit is old and/or there aren’t any qualified generator specialists in your area, a new replacement generator is likely the best option.

While not inexpensive (the unit installed here cost around $3,575) a new generator can be installed with common hand tools and some mechanical/electrical experience. To see how it’s done, we visited C&S RV Service in Oxnard, California, and observed as an older Onan MicroQuiet 4000 generator was replaced with a newer Onan QG 4000 model in a 2006 Fleetwood Tioga that had been purchased used. The previous owner had neglected to maintain the generator to the point that it had seized, but the motorhome was in otherwise like-new condition. The project was completed by a professional in about four hours, but your results will obviously vary depending on the generator, the motorhome and your skill level. And remember, always call a qualified RV repair center if you’re not comfortable completing a job like this yourself.

The first step is to pull out the Weather Pack connector to the remote-control unit
Next, the battery power cable is disconnected
The first step is to pull out the Weather Pack connector to the remote-control unit, which allows remote starting from the switch inside the motorhome. Next, the battery power cable is disconnected.
Moving underneath the motorhome, disconnect the ground cable followed by the rubber fuel line
The technician used an old spark plug in the line after it was cut to prevent fuel from dripping
Moving underneath the motorhome, disconnect the ground cable followed by the rubber fuel line. In most cases where the generator is several years old the fuel line will be brittle and difficult to remove, so it will likely be easier to cut it off. The technician used an old spark plug in the line after it was cut to prevent fuel from dripping.
This older motorhome was not equipped with an automatic transfer switch, so the next step was to disassemble and remove the junction box in a cargo compartment adjacent to the generator
This older motorhome was not equipped with an automatic transfer switch, so the next step was to disassemble and remove the junction box in a cargo compartment adjacent to the generator.
Removing four screws releases the cover, revealing the wiring inside
Removing four screws releases the cover, revealing the wiring inside. Use a screwdriver to release the white and black wires from the cover.
A useful tip is to mark the inside of the cover so you know where the wires go upon re-assembly: “W” for white, “B” for black; the green ground wire remains attached
A useful tip is to mark the inside of the cover so you know where the wires go upon re-assembly: “W” for white, “B” for black; the green ground wire remains attached.
Next, the exhaust pipe was removed
Next, the exhaust pipe was removed.
A common floor jack and a square piece of plywood is used to support the generator prior to removal of the mounting brackets
A common floor jack and a square piece of plywood is used to support the generator prior to removal of the mounting brackets.
How the generator is mounted at the factory will depend on the motorhome, but in the case of this 2006 Fleetwood Tioga Class C
How the generator is mounted at the factory will depend on the motorhome, but in the case of this 2006 Fleetwood Tioga Class C, it is seated in a metal pan that is secured on both sides by a mounting bracket and two bolts.
Next, the mounting brackets themselves are removed from the sub frame, and the generator can be lowered to the ground
Next, the mounting brackets themselves are removed from the sub frame, and the generator can be lowered to the ground.
Because the new generator does not come with wiring conduit and its attendant hardware, they are removed from the original unit. The 90-degree fitting is removed first and the conduit slid off
Because the new generator does not come with wiring conduit and its attendant hardware, they are removed from the original unit. The 90-degree fitting is removed first and the conduit slid off. The wires from the new generator are then taped together, fed through the conduit and the fitting replaced.
The floor jack is once again employed to lift the new generator in place, and the disassembly procedure is reversed
The floor jack is once again employed to lift the new generator in place, and the disassembly procedure is reversed.
A new Onan generator should come from the factory filled with oil. However, it’s a good idea to check the dipstick before running, just to be sure
A new Onan generator should come from the factory filled with oil. However, it’s a good idea to check the dipstick before running, just to be sure.
Next, this rocker switch is used to prime the fuel pump, after which it is clicked to the right to start the generator
Next, this rocker switch is used to prime the fuel pump, after which it is clicked to the right to start the generator.
After the new generator was installed, it was discovered that the original exhaust pipe bracket was broken
After the new generator was installed, it was discovered that the original exhaust pipe bracket was broken. If not properly supported, vibration will eventually cause the new pipe to crack and fail, so the old bracket was replaced with a new rubberized one.
Finally, a circuit tester is used in a 120-volt AC outlet inside the motorhome to make sure the generator was installed properly and is working correctly
Finally, a circuit tester is used in a 120-volt AC outlet inside the motorhome to make sure the generator was installed properly and is working correctly.
Sources:
Cummins Power Generation
power.cummins.com

C&S RV Service Center
(805)-982-9900
www.candsrv.com

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