This is really an extension of what I have posted about my brand new Bobcat E35R2 machine. Today I started the machine and let it warm up I then increased the idle speed of 1240 up to the 1600s and the vibration is still really heavy then I went up to the maximum rpm or 2450 and it smoothed out. My question before their mechanic gets here is, is that a normal thing? Some have said their machines do similar things but I find it hard to believe that a good running engine would have that vibration at any rpm. What are your thoughts? I would like them, if they cant get that engine smooth at all rpms to take it back and then i would go in to the dealership and test run all their machines to see if they all do it or not. Does that sound reasonable? Regards, Joe
When you have an engine driving anything, in this case it has a hydraulic pump or three hooked up to it, there is generally always an RPM range at which some resonant frequency produces a vibration that can be felt. One particular model I recall idled smooth as silk at 700 RPM, sounded like a bucket of bolts at 1300 RPM, and at full 1850 RPM - also smooth. I guess the $64k question is does the operator manual recommend that the machine should usually be run in a specific fashion for maximum hydraulic efficiency, cooling system performance, economy, or whatever other parameter you can think of.? Running excavators at less than full engine speed is a somewhat unusual circumstance in my experience. I would say that if you could run a couple of other identical machines and check for the same pattern of vibration (or not as the case may be) only then would you be able to confirm or deny the salesman's "they all do that sir" comment or not....... YMMV.
Thanks great advice
Somewhat anecdotal; but the 3 cylinders (Yanmar, Kubota, Isuzu, Cat--Mitsubishi) I am familiar with always smoothed right out with just a small (~200-300) rpm increase from low idle. Then they (engines/hydraulics) were nice and smooth right through the rest of the rpm band. It would be good if you could hop on an identical machine in order to confirm the abnormality of the issues you are having (as Nige says above) Good luck! This sure must be disappointing in a brand new machine...
Thanks and yes very disappointing. Hope it gets resolved as I did quite a bit of due diligence before purchasing this machine, I would have preferred a Cat but sometimes dollars rule common sense :-(