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BobCat FastCat won't start

Discussion in 'Mechanic and Repair' started by the4hornes, Jul 5, 2013.

  1. the4hornes

    the4hornes LawnSite Member
    Posts: 15

    Can anyone help me troubleshoot my Bobcat FastCat 48" 19hp KAW ZTR mower? I thought the solenoid was bad, but today I put 12v across the 2 small terminals (on the solenoid) and the motor turned over. I checked the 2 safety switches for the control handles, the seat safety switch, and the parking break safety switch. They all were OK. After cranking, by shorting across the solenoid, the mower runs fine. Any suggestions on how to troubleshoot?
    Thanks,
    Mark
     
  2. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Posts: 2,231

    Do you have a 4 post solenoid or a 3 post? If it only a three post, with a
    12V test light, attach the clamp end to an engine ground and touch the point end of the test light on the small post(switch leg) of the solenoid. If you turn the switch to the start position, you normally should have power at that post---that's what activates the plunger coil/bar in the solenoid to transfer power from the battery post to the starter post(an operation similar to what you did in jumping one post to the other). If you don't have power there you've likely got a bad switch.

    The only difference between a 3 and 4 post solenoid is that the 4 post has two small connectors--one is the switch leg, the other connection goes to ground. If you have no power to either one with the switch turned to the start position--same situation, a likely defective ignition switch. If you do have power at the switch leg, check the other small wire that goes to ground--you could have a loose connection there, not permitting the solenoid to activate.
     
    Last edited: Jul 5, 2013
  3. the4hornes

    the4hornes LawnSite Member
    Posts: 15

    Thanks for the reply Dutch1. I have the 4 post solenoid. I'll check for voltage on the post when the ignition switch is turned on, and the ground connection on one of the posts.
     
  4. herler

    herler LawnSite Fanatic
    Posts: 5,145

    Have you tried reading the Owner's Manual?

    It could be as simple as the fuse...
     
  5. the4hornes

    the4hornes LawnSite Member
    Posts: 15

    Checked fuses first. They were OK.
     
  6. the4hornes

    the4hornes LawnSite Member
    Posts: 15

    I got a chance to troubleshoot my Bobcat today, but still no resolution. I double checked all of the safety switches, the fuses, the solenoid, and the ignition switch. My solenoid has 4 posts. I am not getting 12v on the 2 small poles on the solenoid when I turn the key. I switched the 3 relays around, so I feel like they are not the problem. I hear the relay click when I turn the key to run, but no other noises. I checked the wiring to the solenoid, and they seem ok. The motor will crank and run if I put 12v on the 2small posts on the solenoid or short the 2 big posts. Any more suggestions? Here is my manual http://www.oscar-wilson.com/MANUALS/BOBCAT/4146185.PDF
     
  7. Jeff in AL

    Jeff in AL LawnSite Senior Member
    from Alabama
    Posts: 718

    The4hornes,

    See reference number 15 in the attached file below...

    The solenoid has 4 terminals and are referenced as 1, 2, 3 and 4. Terminals 1 and 2 are positive battery terminals and terminals 3 and 4 are the trigger and ground terminals.

    Being that you have "checked" all of the safety switches I will assume by that you have a DVM and checked them in the NO and NC positions to rule them out... But in case you didn't, you can do so correctly by following the steps below...

    So take your DVM and take a reading of the battery voltage prior to starting unit.

    Make sure both Traction Levers are fully open, Parking Brake is fully on and PTO is off.

    Now take your DVM and ground the negative probe either to the battery or to terminal 3 or 4 which ever has the Black ground wire(s) on it. Then take the positive probe and go to terminals 3 and 4 and connect to the terminal that has the Yellow wire with a Black Stripe on it.

    Now try to start the machine and take a reading with the key in the START position. You should be getting battery voltage at this time.

    If you didn't get battery voltage at that time, you have a problem back in a Safety switch, Relay, Ignition switch, PTO switch or fuse.

    If you did get battery voltage at that time then it appears you have a bad solenoid... However, being that you said that you applied 12 volts to the number 3 and 4 terminals and it started it sounds like your solenoid is ok and that your problem is back to a safety switch or the like listed above.

    IF you find that your problem is back to a safety switch or the like, you will need to start tracking where you are losing the hot path. I would suggest printing the Harness Schematic and start at the Ignition Switch and go from there.

    NOTE... From this point on, make sure the Parking Brake is ON, both Traction Levers are fully open and PTO Switch is off!

    A quick shortcut to check the Ignition switch, ALL safety switches and PTO switch is to check for battery voltage at the Start Relay... Look at the 3 Relays and find the one with 2 Black wires, 2 Brown wires, 1 Yellow wire and 1Yellow wire with a Black Stripe going to it (should be the middle Relay)...Check for battery voltage at the Brown wires with the key in the Run position, both Traction Levers fully open, PTO off and Parking Brake on... If you do have battery voltage and the unit won't start you have a bad Relay. If you don't have battery voltage, then you have a problem with any of the switches.

    How to check the switches step by step...

    First make sure you have battery voltage to the "B" terminal (Red Wire from fuse) on the Ignition Switch in the RUN position. If you do then move on... If not, then the fuse in the red wire is the issue, but you said it was ok...
    Then check the Ignition Switch and see if you have battery voltage on the "S" terminal (Yellow Wire) in the START position. If you don't, the Ignition Switch is bad. If you do, then move on...

    Next would be to see if you have battery voltage on the "L" terminal (Orange Wire) at the Ignition Switch in the RUN position. If you dont, the Ignition Switch is bad. If you do, then move on...

    Now check for battery voltage on the Orange wire with a Black Stripe on the PTO Switch with the key in the Run position. If you don't, then the PTO Switch is bad. If you do, then move on...

    Now check the Right Traction lever switch... (You can double check and see if you still have battery voltage on the Orange Wire with the Black Stripe at the switch, but you should)... Check and see if you have battery voltage on the Purple Wire with an Orange Stripe coming out of the Right Traction Lever switch with the Traction Lever fully open and the key in the Run position. If you don't, the switch is bad. If you do, then move on...

    Next check the Left Traction Lever switch... Check and see if you have battery voltage on the Orange Wire with a Purple Stripe coming out of the Left Traction Lever switch with the traction lever fully open and the key in Run position. If you don't, the switch is bad. If you do, then move on...

    Next check the Parking Brake switch... Check and see if you have battery voltage on the Brown wire coming from the Parking Brake switch with both Traction Levers open, Parking Brake on and key in the Run position. If you don't, the switch is bad. If you do, then move on...

    At this point, you have fully checked and ruled out the Ignition Switch, PTO switch, both Traction Lever safety switches and the Parking Brake switch as the problem.

    By now, you should have found the problem or cause for your machine not starting!

    Have fun and good luck!
     

    Attached Files:

    Last edited: Jul 14, 2013
  8. the4hornes

    the4hornes LawnSite Member
    Posts: 15

    Thanks Jeff in AL! With your help I found that I have a bad wire in my wiring harness (or a bad crimp on the connector). The purple and orange wire that runs between the left and right traction lever is is bad. I wasn't getting voltage on the purple/orange on the left lever. I measured for connectivity and it was open. I ran a temp jumper wire and the motor cranked. I will post a good wiring diagram that I got from Bobcat when I get a chance.
     
  9. the4hornes

    the4hornes LawnSite Member
    Posts: 15

    Here is the color wiring schematic that BobCat sent me for the BobCat Fastcat.
     

    Attached Files:

  10. Jeff in AL

    Jeff in AL LawnSite Senior Member
    from Alabama
    Posts: 718

    the4hornes,

    Glad to help and happy to hear you found the problem!
     

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