Severe vibration & shake at low idle

[Rip]

I am looking a used 1500 hr F-series machine with the D1105 engine that has a severe vibration & shakes everything at low idle......goes nice & smooth once above about 1000+ RPM (has no tach). Is idle set too low or is this 'normal' ?? For this engine or others? I have similar size NH and a larger Deutz all 3 cyl that are much smoother at idle.....also a Toolcat with a Kubota engine idles smoothly.

Basically, should I be concerned as it smooths right out above this low idle?? Almost feels like it is only running on 2 cyl at idle.

[kuboman]

sounds like mine. If the idle has been set down some then it will shake. The engine is mounted in rubber so it tends to shake more. How many hours on the machine? If the rubber mounts get worn it will shake even worse.

[unbidden]

Can't speak for the idle on that particular machine but the manual for my BX states idle should be 1300-1400 if I remember correctly.

[dodge man]

My Bx has what I assume is a similar 3 cylinder engine, just smaller, and it shakes pretty bad at idle. If you kick it up a few hundred RPM,s it smooths out.

[Rip]

Thanks all for the reply.....the machine is a 2009 with bit over 1500 hrs on it......was used pretty much every day by a municipality so not 'babied' by a loving owner! It is still at the dealer but will have them take a good look at the engine mounts. A broken mount may be fairly obvious, but how does a worn mount look? I want as much sorted out BEFORE they deliver it and I pay for it as possible as it will be a pain after that I can tell.

[kuboman]

It would be best to have a new mount to compare to but they will start to compress/sag. The rubber will take on the old cracked look. 1500hrs is quite a few. I had a JD with 2000hrs and the mounts were shot. Kubotas are a little different design but same idea. The rubber also tends to lose some of its integrity and may look ok but not be as strong. I doubt they are all that pricey and should not be that hard to change.

[Rip]

Thanks Kuboman, I will have them check and report on the motor mounts while it is still there......if they are in fact still good, may have them set the idle up also. This was a municipal machine so was heavily (and perhaps more than a bit roughly) used, but should have lots of life left and suit my needs better than most anything else.

[kuboman]

The F series are serious mowing machines and there should be a lot of years left in yours. One other thought is you might have a slightly weak injector that will cause more shaking at idle. If the mounts check out ok you could have the injectors set up. All depends on how much you want to spend. Personally I would run it a while with a good fuel conditioner and see if it smooths out any.

[Rip]

I am trying to get the dealer to make this machine as 'right' as possible especially as they advertised it as having had '...regular services done by **** Farm Equipment" when that turned out to not really be the case after the first 50 hr service.....so trying to get them to deal with anything I can identify at this point since I'll be on my own soon enough.

What brands of fuel conditioner have you found worked best? Bio-fouling probably more of a concern here than gelling.

[kuboman]

Unless it has a noticeable very slight miss I would not worry about the injectors at this time. It is just a possibility that I mentioned. As for fuel conditioner I have used Stanadyne performance formula with noticeable results. I am a believer in fuel conditioners but you can do a search and get more opinions and advice that will keep you reading for years.
I am assuming you are getting all the fluids and filters changed??