Yanmar Vio55-6 with Flail Mower - Stick Wont Move Out

[nskyline34]

Hey everyone, I've got a Yanmar Vio55-6 excavator with about 550hrs on it and a US Mower EX40 Flail Mower that I'm having some issues with. I've used US Mower products a lot and have had great luck with them but I'm stumped on this one. I connected everything up to the excavator and it worked great... sort of. The mower spins up great and while connected to the mower the machine works/operates fine. When you run the mower and track it obviously is a little slower than normal but makes sense becuase you're running the mower too. Same with all of the other functions - they work fine while running the mower, a little slower than normal, but fine considering the mower is running at the same time and sucking up some hp... Its all good right up until you try to move the stick/mower out away from you with the mower running. When the mower is as close to the boom as possible it will go out fine until the stick gets to the vertical position (gravity is helping) and then when you try to go out past that vertical position it will go super slowly for about 2' and then it will stop moving out. (again, all of this is while the mower is running). The second you let off the PTO button to disengage the mower the stick will shoot out like normal and operates perfect.

Mower is new, and they even gave me a little larger motor to swap into it becuase the one that was originally on it was a little small for its flow rating, but still the same thing is happening. The machine has 550h on it and all the filters are brand new. Machine operates flawlessly when digging and every function except moving the stick out works fine while the mower is running.

I'm wondering why this would be and if anyone has any ideas?

 

[heymccall]

It can only make 24gpm of flow total.
Not sure that a 40gpm mower is a good match.

 

[nskyline34]

Had the machine tested - it flows 32 gallons and is 1,800 psi. EX40 = 40" mower, not 40 gallons of flow required. 1st hydraulic motor was sized for approx 22 gallons, the one I have now is for 29 gallons. Not really a difference in performance between the two as far as the issue I'm having is concerned.

 

[JD955SC]

It is common when using high flow attachments to lose a function and it can be to that extent easily when you are using that much of available flow. Your machine does not have the hydraulic power to spare.

I try to encourage an oversize machine vs just going off of specs for this very reason. In spec for the mower means it will run it, not necessarily that you will have functions and running the mower (This is a concept the sales department can struggle with, but I digress).

There is good reason that machines like the Shinn Systems modified mulcher carriers exist- by providing a power pack dedicated to the mulcher the carrier machine will never lose a function.

 

[heymccall]

Had the machine tested - it flows 32 gallons and is 1,800 psi. EX40 = 40" mower, not 40 gallons of flow required. 1st hydraulic motor was sized for approx 22 gallons, the one I have now is for 29 gallons. Not really a difference in performance between the two as far as the issue I'm having is concerned.

I didn't assume EX40 meant 40gpm. I actually googled it.


If anything, the "29gpm" motor should be worse.

 

[heymccall]

Are you operating in one way or two way mode?

 

[nskyline34]

They say 15-40 gpm because they look up the specs and size the motor for your machine. They looked up the specs on the first one and sized the motor for 21gpm, I then told them the issues and they asked me to go actually have it flow tested, that's when I found the machine actually flowed 32gpm, so they had me try the next size up motor thinking maybe it was limiting the flow or something and not letting the rest of the machine function correctly.

I'm not trying to use an attachment too large for the machine - I've had them correctly matched...at least I thought... Unless I have them give me a motor for 15gpm and I try that? Then I should have PLENTY of extra flow?

And yup - its in single acting.

 

[nskyline34]

Now I totally agree with you guys that if I'm asking the machine to run something way too big for itself - then I have zero room to complain! lol Like the skid steer I have flows 17gpm and runs a mower that requires 20gpm... Its performance definitely isnt optimal, but that's what I signed up for when I made the choice to pair a mower thats a little too big for it. But this feels a little different to me... or am I wrong? lol

 

[Envirodemo]

Just wondering if you ever figured anything out on this , I’m Having the same problem with my vio 55-6 with a brush cutter

 

[imjustdave]

I would suspect the motion - action that take the leaser flow to do something gets the fluid.
So mower rotating take X HP and the drive motor while slower is less HP demand so the machine moves.
But when the stick or boom to go UP takes more power than spinning the motor all the flow goes to the mower. Basically opening up the valve has no impact... it might as well be closed.

IF the machine had dedicated pumps to certain functions VS shared it would act differently.
I like the idea of mower/mulching heads on an excavator but on a mini I'm not sure I'm sold on their use past niche applications VS big area