Yamaha ydre wont't run

[Volt_Ampere]

You should measure from A1 to A2 when trying to run. That is the voltage applied by the controller which will be zero when stopped. F1 to F2 will be the field voltage which is also interesting but unlikely to be your problem if brushes have failed.

[ojo]

Thanks, i'm going to repeat it asap!

[ojo]

So, i've tried again... as mentioned yesterday, there are 50+ v on both A1/A2 in stillstand and 0v when messured between A1/A2 and that's with or without accelerating!

[Volt_Ampere]

If you are getting 0V from A1 to A2, the controller is not giving the motor any voltage so it is probably not the motor. Is the solenoid clicking when you press the pedal?

[ojo]

Yes, solenoid clicks normal and shuts off after a few seconds when the pedal is lifted...

But, when key is turned to on, no click from solenoid, and when key on off, there is still power on both posts ( 51.6v right from battery, 50.2v left side to controller ). For me, the solenoid didn't really shuts off??

[Volt_Ampere]

That is normal. There is a "precharge resistor" across the solenoid which puts almost full voltage across it even when the solenoid is open.

[camaroluvz28]

Had one doing something similar yesterday I thought was bad motor...symptoms were...when placed in run - solenoid clicked...wait a 10 seconds solenoid clicked off- turned key on-solenoid clicked and turned off ten seconds - apply pedal solenoid click no movement then clicked back off, BUT would not reclick with pedal after that...turned out to be solenoid dropping out causing fault - would do every time the run/tow was switched in the same order... Place negative probe of meter on main negative battery pack and positive probe on large post of solenoid that connects to controller...do the sequence I just said and watch for solenoid to quickly drop voltage to 0 once pedal is depressed..If so Solenoid is defective if its anything like the one I just repaired...

[ojo]

Just attached the dvm as you described. From tow to run, voltage is 50.1v, with the pedal pressed it's raising to 51.4v, solenoid clicks on/off several times when pressed/depressed. What i actually noticed, there is a hum to hear, as long as the pedal is used.

[camaroluvz28]

sounds like your getting power all the way through solenoid...meaning it really can only be one of three things... Controller/Motor/Throttle Sensor...I would personally pull the motor and check the brushes just to eliminate it as an issue...It is one of the most common problems with this cart and I change brushes out at least three times a week...

[ojo]

Yes, thank you! I agree with the brushes. I'm not sure with the voltage on A1/A2 at all time... Can i get them out without pulling the whole motor?