Bobcat 225 voltage test help

[Rscott]

Recently purchased a used 225 knowing there was a high idle issue. Welder idle solenoid was stuck in a high idle position. Removed and cleaned, still does not work. Started checking voltage. No voltage at solenoid so I checked at the pull to idle module. With the switch turned on to the run idle position I have 12vdc at the H 12v switched. No voltage at the B 12v terminal or wire. Traced B wire back to the Diode mounted beside a fuse. All fuses are good. I do not know which way to proceed from here.

[Rscott]

Kohler Engine.

[Torchplasmasales]

Check the idle cotroller PCB. Its mounted behind the panel.

[Rscott]

Is that the orange box behind panel that’s called the pull to idle module?

[Torchplasmasales]

yes.

[Torchplasmasales]

I think I remember it being a 3rd party module and datasheets and/or pinouts are available on google. I don't have a bobcat anymore so I cant confirm that for you.

[Rscott]

I don’t see anything else.

[Torchplasmasales]

Sorry, I'm not following you. This is the module I was talking about

https://www.amazon.com/Miller-201936...51656973&psc=1

It monitors the current demanded from the generator (I think) and commands the idle solenoid to increase or decrease the RPMs accordingly. Read the voltage between output and common and see if it makes sense based on what the machine is doing.

[Rscott]

That’s the module I was talking about. Upon further testing tonight, with the switch in the run/idle position with machine not running, there is 12vdc at terminal H, if you turn switch to run position that voltage goes away.
With the engine running, same voltage at H, and also I now have 12vdc at terminal B.
I did not try to measure voltage at terminal C Output but it did not light a 12vdc test light. I plugged in a grinder in the A/C outlet and powered it on, still nothing at the Output C. I traced Output C back to the + wire that connects the idle solenoid at the carb.
im not sure where and what voltages should be showing up. And I’ve not figured out how to search this forum.

[blue_tech]

Do you have a serial number so I can better point you in the right direction to test?

[Rscott]

Lf321641

[blue_tech]

I can dig deeper and get exactly the correct circuit diagram to help troubleshoot this, but that serial number pulled up as a Suitcase feeder. Can you please confirm the serial number?

That being said, most of these engine drives only energize the throttle control solenoid when it needs to go to idle. So saying it is stuck in the high idle is not completely accurate. In fact, by design, it is built that way so that if it stays at run speed and you can keep using it, vs being stuck at idle not able to energize the throttle control just to get to run speed.

[Rscott]

Wrong terminology on my part. Correct, it’s not stuck at high idle, it’s just running at high idle, I can manually pull the governor arm back to idle. There is no voltage coming to the solenoid. There is no voltage at the idle module on the output terminal.

[blue_tech]

When you place the switch to the idle position a signal is sent to the idle control and it should then send power to the throttle solenoid. If I can find out for sure what unit you have, I can tell you where this signal would be measured.

[Rscott]