Thor Forums

[Chance]

Originally Posted by eccentricson

That's a great point. I think I'm at the next stage of my mindset, rather than throw money at it and replace the generator, fix the vibration and rough start. Just need to figure out what mount points are causing it to shake the entire coach when it turns off.

In my opinion it’s smart to accept 4,000-Watt generator. Going larger to 5,500 will cost a lot, creates additional problems, adds weight, and consumes more fuel when running at lower percentage of rated power/capacity. It’s not worth it unless you add a second air conditioner and upgrade to 50-Amp electrical. Designers of some of the newest motorhomes seem to be trying to get rid of generators, so this 4000-to-5500 upgrade is a step backwards in my view.


My opinion on vibration as generator turns off is that much of it is normal. If you haven’t experienced this before, it may seem excessive, but perhaps it’s only your personal perception and expectation that it should be smoother. You may want to check other Onan 4,000-Watt generators.

The 4,000-Watt Onan engine is single cylinder and runs at 3,600 RPM, so it vibrates quite a bit. It’s normal to have vibration isolators (they’re not technically dampers) that allow engine to shake without transferring as much vibration to the motorhome. Problem is that if the isolators are tuned for 3,600 RPM (the speed the generator runs most of the time) they will not be ideal at low engine speeds as it coast down on shut-down.

Having said that, I’d check the isolators anyway to make sure they are good, but expect that with less than 1,000 hours they should be fine. If the vibration you’re experiencing last for more than a second or two, I’d question if your generator engine is running on instead of shutting off quickly as it should.