Electrical problem on ZD 21 zero turn mower

[Dozernut]

The starter went bad on my ZD 21 and was replaced with a new/rebuilt starter from the dealer. The battery was also replaced and a new end was put on the positive cable. A volt /ohm meter checked the battery cables and showed good. The problem is the mower will not start without a jump on a cold start. The battery was checked and another new battery was tried with the same results. The mower will start if you shut it off after use and restart immediately.

My question, is there a capacitor on the circuit that I am unaware of that boosts the starter at cold start. I am sure it is a simple solution, but I cannot figure it out. Thanks!

 

[David_Kb7uns]

No capacitors involved.

This is just a guess, but some of the equipment will exhibit a non start issue where the starter solenoid will click but not engage the starter because the loop of all the interlock switches, as they age and contacts get oxidation on them, drops the voltage so the starter solenoid does not kick all the way in making contact with the starter terminals.

Had this issue on my G2160 diesel mower where it would not start first time unless you had charger attached. John Deere has had similar problems and they came up with a low volt relay that would be mounted on the starter and it would complete the loop from the battery terminal to the solenoid terminal. Since I installed the relay have had no issues starting. The kit has a relay and a socket with wiring but I just got a standard 30amp automotive relay and wired it in for about $12. If you are careful and know what you are doing you can try a jumper wire next time and see if you can get it to start.

John Deere Starting Improvement kit.
John Deere Starting Improvement Relay Kit - AM17421

Depending on application some terminals need to be changed, a generic good quality relay may be a better choice

David

 

[100 td]

If it starts with a jump there is a bad connection or wiring/voltage drop problem somewhere, and new batteries can be poor. Also recheck the new lug on the cable and battery terminals, it could be a poor connection. Check your grounds as well.
WHEn is it that it won't start and needs to be jumped, after an hour, or the next day?

 

[Dozernut]

Thanks for the reply, the internet was down so I could not reply sooner. David, I believe you might be on the right track I will check and see if our local Big R store has them in stock.
I did not think there was a capacitor on the machine, but when I get to thinking I get in trouble. The symptoms mimic a bad capacitor.

100 td: the mower will not restart on it's own after sitting for 15 to 20 minutes.

Thanks again for your replies!

RB

 

[100 td]

While the addition of extra wiring and relays may help, ideally you need to fix the cause, not the symptom.

If the engine will start with the simple addition of a jumper battery, you have a problem with the battery, and/or wiring.
I expect your battery is faulty, or there is a drain on the battery when the engine is shut down.
A simple test can help prove this.
When your engine is cold, completely disconnect the battery.
Then get your jumper/booster cables and hook up your car or truck battery directly to the battery leads, ensuring that when you do this they are adequately insulated from each other, are not touching anything metallic and when the engine starts they won't/can't fall or move and short out to each other or anything metallic.

If your engine will not start, it won't matter whether it's hot or cold, you have a problem somewhere which needs to be rectified. Fix the cause not the symptom.
If it doesn't start, first check the usual, seat switch, hand brake switch, PTO disengaged switch etc.
Then if it doesn't start, remove the negative jumper cable and clamp it directly to good clean un-painted metal on the engine and try again.
If that doesn't work, disconnect the positive cable and CAREFULLY clamp to the main lead wire on the starter motor, ensuring it doesn't short out, and try again.

Please note, using jumper cables is fraught with danger if you accidentally short or incorrectly connect the wires to something as arcing and sparking and large short circuits currents can flow. If you are unaware of this or are at all concerned, do not proceed without professional help.

 

[Dozernut]

David

Sorry for the late response to your suggestion of the starter relay kit. The kit worked like charm and solved the ZD's starting problems. THANK YOU!!!!!!

I could not find one close so I ordered one off of Amazon. Installing took less than 5 minutes and I would recommend it to anyone have starting problems with their mowers. The instructions are confusing, so I just went by the wiring diagram. Again, thanks for your input as I was able to quit banging my head against the wall.