SVL75-2 High Engine Idle

[gwg55]

I have a 2020 SVL75-2 Skid Steer where the engine idle stays high even when turning the speed knob down. It will increase a little by turning the knob up but will not idle down. It just started one day without any other issues. Not sure what to check. Thanks

 

[GreensvilleJay]

curious...'speed knob'...what's it connected to ??? mechanical or electrical control over 'idle' ??
WSM is really needed !

 

[gwg55]

It’s an electrical input probably to the ECM or maybe a solenoid on the throttle linkage. Not sure. Manual is not very clear. No troubleshooting help in the manual.

 

[GreensvilleJay]

Curious...

Is THIS the 'knob' you're talking about ? #070 that operates #060

 

[gwg55]

Yes it is

 

[GreensvilleJay]

OK, progress...
Now ,can you spin the knob, around and around, or just say 10 oclock to 2 oclock ?
if the 1st, it's an 'encoder', the 2nd, it's probably just a 'pot'.
If easy, disconnect from the wiring harness and count the connections, 4 it's and encoder, 3 it's a pot.
You try blowing LOW pressure air around it, connect/disconnect cable a few times...might be a 'bad connections'.

 

[gwg55]

Curious thing is that if I turn the knob all the way up the engine speed goes up a little more. But when turned all the way down it only goes back down that little bit but stays very high.

 

[gwg55]

It will not turn round and around. Has a definite stop in both directions.

 

[gwg55]

It does sound like the control pot.

 

[GreensvilleJay]

OK, odds are it IS a pot ( like a volume control in radio)
The WSM will have a wiring diagram, bet it show 3 connections.
If a pot, it's a variable resistor, 2 ends and a wiper( part that moves). If you've heard a radio volume go high and 'scratchy' that's the wiper moving carbon crud around. If the wiper gets disconnected, no voltage is sent to the 'computer', so no change in ,this case, idle RPM'.
You might try a spritz of brake cleaner and then low pressure compressed air.

 

[gwg55]

Where di you find that schematic of the switch assembly? I can't find in my manual. Thanks

 

[gwg55]

I will try your recommendation. Thanks

 

[gwg55]

The knob does only goes 10 oclock to 2 oclock like you said.

 

[GreensvilleJay]

If you mean the picture I posted, it's from Kubota online parts pages....

If you mean how do I know 'how it works' ? I'm drawing on 6 decades of electronics experience,from vacuum tube amplifiers, avionics,building mini computers and programming microcomputers

 

[gwg55]

Not questioning your expertise at all. I’ve been in my manuals and online and can’t find that diagram.

 

[Russell King]

Not questioning your expertise at all. I’ve been in my manuals and online and can’t find that diagram.

Go to KubotaUSA dot com and then illustrated parts list. Agree to the terms, search for your model and be general and then select your specific model from a list, then go to parts on the left side and find the correct diagram (probably under the electrical in your case)

Can also use Messicks site that is similar for parts lists

 

[gwg55]

Funny I have a login for both and my model is in my setup but that diagram did not come up. I’ve dealt with aircraft maintenance manuals my whole life but theses are not the same. I’m checking my larger wiring prints also. Thanks for all your help.

 

[GreensvilleJay]

from Canada's 'parts' finder
model ...' svl75-2'
chose 'electrical'
chose 'B40300 sensor'

I can't access KubotaUSA ( they don't like me.....)

 

[gwg55]

Thanks

 

[#40Fan]

https://kpad.kubota.com/books/2608/figs/158986

Hope the link works, but I bet it will just take you to the main page.