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JLG 500RTS Scissor Lift.... Will Not Throttle Up And Hydraulics Will Not Work

Discussion in 'Other Construction/Demolition Equipment' started by crashtriple3, Jul 16, 2018.

  1. crashtriple3

    crashtriple3 New Member

    Jul 16, 2018
    Erie PA

    I just bought a 1996 JLG 500rts Gas (not dual fuel) LRG-425 i believe.... with approx only 750hrs

    Used a few times now and all seemed fine until today. Before todays use it was sitting for about 2-3 weeks without running.

    First 20 minutes all good and then....

    The first issue i started having today was that the throttle would not throttle up when the control switch was turned to "rabbit". It continued to work ok on low speed and then started stalling out when putting the outriggers down.

    From here i tried to push the throttle actuator linkage while simultaneously hitting one of the switches that puts the out rigger down and the hydraulics seemed to work fine, pump engaged, engine started to bog down almost stalling, i then manually moved the throttle open to keep it running, out rigger when up and down fine as long as i keep the rpms up.

    As the day went on i checked wires by wiggling them for loose connections, unplugged the controller connection, air blew it out, light brush/clean, Fresh gas in the tank as well. simple things

    Now at the end of the day all it will do now is run at low rpm. I try to put outriggers down and nothing happens except they would so very slowly move down but the motor didn't bog down like it was under load or the pump wasn't engaging. Nothing

    I'm no expert, pretty handy and have decent knowledge of gasoline engines but very new to the world of hydraulics. So from my novice observation it appears that the solenoids for hydraulics were working hence the very very slow fall of an out riggers when switch was pressed but the pump would not kick in.

    And still it would not respond at all to the high/low throttle switch and would only run at low rpms.

    Thoughts? Relays? It just seems to me that something, or a few things, are not "talking" to other things in the electronics.