Onan 10,000 bad vibration

[Stump Jumper]

Started up the generator yesterday in 34 degree weather in order to give it some excercise. Noticed a very bad vibration. It almost seems like a motor mount has gone bad. 2019 model with 209 hours on the generator and I have not had time to pull it out and take a look. Has anyone else experienced this on a new generator?

[96 Wideglide]

Any smoke from the exhaust?

[Stump Jumper]

No smoke and it powered everything up fine. Seems to run fine, just feels like a metal on metal vibration like a motor mount. Didn't know if this was a known issue with these?

[96 Wideglide]

Don't believe it's a common issue.

Guess you'll have to crawl under there while it's running and look / feel around.

[Stump Jumper]

Had a chance to work on it today. Seems to work fine with no vibration when it is extended but has a lot of vibration when it is retracted inside the motorhome. Had my Son extend and retract it while I was under the coach. There are 4 rollers mounted to the frame that the generator rides on. When the generator is retracted, it is sitting on the front two rollers but not on the back two. I would assume it should be sitting solidly on all 4 rollers. I think this might be why I am getting vibration when the generator is retracted but not when extended. Looks like I am going to either have to re drill and remount the back rollers or weld a shim on each side of the generator slide so that the generator sits solidly on all 4 rollers. Should have mentioned earlier that this motorhome is new to us and when we tested the generator, the slide was out.

[96 Wideglide]

That's odd it would be sitting on only the front rollers !

It weighs several hundred pounds.

[Stump Jumper]

I thought so too. It looks like it is only built to rest on all 4 slides when the generator is almost fully retracted. The rollers that I am referring to are located under the generator.

[96 Wideglide]

Originally Posted by Stump Jumper

The rollers that I am referring to are located under the generator.

Yeah, but what could possibly cause the back two to raise off the rails when the slide is completely retracted. I would think the weight is fairly evenly balanced front and back.

[96 Wideglide]

Rollers look like they are lined up evenly side to side on the rails / track they run on?
Possibly hit a bump and the whole assembly jumped up and got misaligned?

[Stump Jumper]

It is strange. The back two never make contact with the rails, ever. When the generator slide if fully retracted, it looks like there is about 1/16" or 1/8" space between the roller and the generator slide frame.

[Stump Jumper]

The crazy thing is, it slides in/out just fine.

[96 Wideglide]

Originally Posted by Stump Jumper

It is strange. The back two never make contact with the rails, ever. When the generator slide if fully retracted, it looks like there is about 1/16" or 1/8" space between the roller and the generator slide frame.

You would think if that were the case, the vibration would have always been there .

[Roger G]

I had the same vibration. Vibrated like crazy slid in but would smooth out when extended. It was a collapsed motor mount allowing metal to touch metal. An easy way to diagnose, crawl under the generator and observe the oil drain plug. With new mounts the bottom of the oil plug should be close to even with the steel plate with the hole that allows access to the plug. If the plug extends through the hole then you likely have a collapsed mount. The unit is supported by three cone shaped mounts with two on one side and a single mount on the other, it’s always the single that collapses. Onan had a bunch of bad mounts around 2013-2015 model years but other years aren’t immune to this. The good news is the mounts are inexpensive and it’s a fairly simple job if you are mechanically inclined. The bad news is that the generator has to come out of the MH and requires a forklift or an engine lift.

[Roger G]

I never could explain why it stopped when extended. The best explanation I could come up with was extended the unit flexed something that allowed clearance.