Cub Cadet shorts on key release and won't start

Discussion in 'Mechanic and Repair' started by cantfix, Aug 13, 2007.

  1. cantfix

    cantfix LawnSite Member
    Messages: 5

    Hello all,

    New poster to the forum but always enjoy the great information I find here, very consistent. I have a question regarding a mower that I purchased from family recently that needs to be driven out of location due to inability to bring in something to haul it and almost 2 miles to push. Service will not visit until Fall, too busy.

    I have a Cub Cadet, RZT 44 I believe, zero turn mower that will not start. The mower was little used and then held in storage for almost two years. It worked well to that point and had only been owned for about 6-8 months with no problems but then parked. It is an 18HP Briggs Twin (Vanguard?).

    Since trying to revive here are the symptoms and what has been done, unfortunately it is in a hard location to get it to a shop and I’m hoping to get some direction. Remember it sat for the last 2 years.

    Our first step was to blow and brush the machine clean and replace fluids, barn housed. We then spun the flywheel to ensure it was not seized, it wasn’t, and that we felt resistance from compression, we did.

    Handles were in “Neutral” position, choked, pto off, braked, etc. Upon turning the key we can/could hear the starter spin but saw that the “bidex” did not engage the flywheel gear to turn the engine, then upon immediate release of the key the fuse blows.

    We can however hold the key in the start position and see the starter spin the bindex indefinitely, but it won’t engage and fuse always blows. The fuse was a 20a and a 30a was tried for good measure.

    Our local Cub dealer (a real dealer not chain), who sold the mower to my father originally, said replace the bindex and the inability to turn the mower over shorted the fuse. Bindex is now replaced and same exact symptoms as before.

    I have searched the Internet and can’t find my exact situation described. What really confuses me is even if a short occurs upon key release why won’t the starter bindex engage the flywheel anyway.

    From reading I am thinking shorts and bad switches but seemingly it should start regardless since the starter is spinning the bindex gear but gears never meet to attempt to turn the engine.

    Could the ignition switch be faulty and a voltage drop be preventing the starter from reaching a rpm fast enough to engage? Is solenoid an issue here? Ants in contacts or faulty safety switch somewhere but why the blown fuse and half working bidex/starter?

    Any takers and if it is obvious educate me, please!

  2. newz7151

    newz7151 LawnSite Silver Member
    from Tejas
    Messages: 2,419

    Did you do a thorough check of the electrical system to make sure mice have not made a mess of wire insulation and now you are shorting somewhere?
  3. fixer67

    fixer67 LawnSite Silver Member
    Messages: 2,098

    OK. this may be a dumb question but recheck the battery and make sure you do not have the wires hooked up wrong. If you hook up the battery wires backwards the starter will spin backwards on a Briggs and the starter gear will not engage the flywheel and when you let go of the key the backfeed from the charging system will blow the fuse. Remember the BLACK wire from the frame goes to the NEG(-) post and the red wire from the solenoid goes to the POS(+).
    I know this may sound like a dumb thing but I have seen it happen more times than I can remember. Batteries come either with the POS(+) on the right or left so you have to look real good at the battery. There are very easy to get hook up backwards.
  4. cantfix

    cantfix LawnSite Member
    Messages: 5

    Thanks for the suggestion newz7151 but except for a light coating of dust the mower is clean, contacts/relays seem strong and clean, all wiring is in its original outer casing, no rusted/corroded parts or evidence that any damage has occurred.

    Truly the harness and all wiring looks like it just rolled out of the factory. My first thought was bugs in a contact so I traced every wire/junction and checked for a good tight contact. Battery is new and I was told by the Cub dealer that that if the starter motor spins the bindex, it wasn't the solenoid.

    I, like you, am still thinking something simple like a bad wire/ground that I missed but hoping to gather a few suggestions before I act again.

    I do wonder in regards to the solenoid but not sure how to tell if one is really good, read a few different "methods", and if a solenoid could cause the behavior.

    It would help to know the possibilities I should consider so I can recheck, at this point if it is not a bad ignition switch, relay, safety switch or solenoid I am guessing broken wire but why the symptoms.

    I plan to put a meter on the wires to check for an internal break but really feel it is something other than a broken wire unless it is internal and all grounds seem fine. If it is a wire break I can't see it and will test for continuity.

    Thanks again however, I will add "recheck wiring for damage" a second time.
  5. cantfix

    cantfix LawnSite Member
    Messages: 5

    I'll check the battery again, no offense taken fixer67. I appreciate all your input. I would love to laugh at myself and bow my head in shame. That is interesting and might explain what I at least feel is odd behavior.

    I am more familiar with AC power systems than DC and a reverse spin is just crazy enough to make me spin and double check.

    Thanks to all in advance who suggest a solution.
  6. Bill Kapaun

    Bill Kapaun LawnSite Senior Member
    Messages: 956

    Probably not much help, but I would disconnect anything electrical that doesn't have to be connected to start the engine. Things like electric PTO, lights etc. MAYBE you could eliminate the short.
    You could also disconnect a couple other things like the Voltage Regulator (it won't charge), the fuel cutoff solenoid (it won't run) to also, at least, try to eliminate/track down the short. That would at least, narrow things down.
  7. Eric D

    Eric D LawnSite Senior Member
    Messages: 295


    My first thought a while reading your post was battery hooked up wrong as fixer67 pointed out.

    Keep us posted on what you find.


    Eric D
  8. John Stiles

    John Stiles LawnSite Member
    Messages: 42

    Is it solid state? Is there an ignition module? That's what it "sounds" like to me....I'm not familiar with your machine. Do you have a wiring diagram?~j>>>>I have seen batteries charged backwards!
  9. fixer67

    fixer67 LawnSite Silver Member
    Messages: 2,098

    On a little side note here. Both types of batteries , the POS on the left and POS on the right are really the SAME battery. What makes them different is how they are charged after they are made. Lead acid batteries are unlike any other battery. In them both plates are the same. If a lead acid battery is 100% dead it will take reverse charge and hold it. My neighbor up on the hill hooked up his battery charge wrong once and the truck battery took and held a reverse charge. When he understood what had happen he just relabeled the battery. The batery lasted for two more years after that.
  10. eaglejrl

    eaglejrl LawnSite Member
    from 75681
    Messages: 63

    Was the dealer you checked with Lasters?

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