Help Troubleshoot why my Zero Turn mower won't start

[Poolshark314]

Running out of ideas on what the issue is. Was mowing my yard with a Husqvarna MZ52 that I have had about 8 years and it shut off in the middle of mowing. Haven't been able to get it started again since.

When I turn the key, there are no clicks or noises, and the hour meter does not come on. So far, I have:

• Replaced the battery. The old one died, but this new one shows 12.6v
• Replaced the starter solenoid. I verified I have 12.6v at the battery side of the solenoid still. I can jump the starter relay and the motor will crank, so the starter itself is good, but it still won't turn all the way over
• Verified continuity on the 2 steering safety switches, the parking brake safety switch, and the seat safety switch (which isn't needed to start)
• Replaced the ignition switch
• PTO switch has correct continuity

Mower has gas, yes parking brake is engaged, yes blades are disengaged

I could not find any info on how the blade deck safety switch works, so not sure if there is a test I can perform for that

 

[Oldsnapper]

It would help to have more information as to year make and model of zero turn mower. All brands are different

 

[Poolshark314]

~2016. As mentioned before, it is a Husqvarna MZ52

 

[BillK]

Have you actually used a volt meter to see if the ignition switch is sending voltage to the starter relay ? Do you have the wiring diagram ?

 

[Firebrick43]

Many ZTR safety switch circuits don’t engage the starter and ignition directly. They have a module with a built in relay and many times an additional automotive relay for the starter.

I have replace my neighbors scag relay twice and the module once.

 

[mm08822]

Here's the wiring diagram I found online. You need to check if for correct year.


Do you have a voltmeter???

 

[Firebrick43]

• Replaced the starter solenoid. I verified I have 12.6v at the battery side of the solenoid still. I can jump the starter relay and the motor will crank, so the starter itself is good, but it still won't turn all the way over

If you jumper with a screwdriver across the solenoids terminal and it does not turn “all the way over” you have a bad starter or a mechanical issue like a broken rod/hydrolocked, ect causing the issue.

 

[mm08822]

This one is per your exact model #

 

[Poolshark314]

If you jumper with a screwdriver across the solenoids terminal and it does not turn “all the way over” you have a bad starter or a mechanical issue like a broken rod/hydrolocked, ect causing the issue.

But using the key, it doesn't crank at all, and the screen doesn't turn on. Wouldn't a bad starter not doing anything even if I jumped it? With a voltmeter, still getting 12.6v at the ground on the starter

 

[Firebrick43]

You might have multiple things wrong.

Jumping across the solenoid should turn the motor over for as long as you hold it no matter what.

It could be a battery cable with an internal break

Also check the ground cable to frame connections. I have seen multiple times that they are sufficient to carry minimal loads for testing but have enough resistance to **** out when cranking

 

[Poolshark314]

This one is per your exact model #

Thanks, the labels on the ignition switch match this diagram, so I should be able to test the key switch positions you posted in your other reply, replacing A1 with L and A2 with A

 

[mm08822]

But using the key, it doesn't crank at all, and the screen doesn't turn on. Wouldn't a bad starter not doing anything even if I jumped it? With a voltmeter, still getting 12.6v at the ground on the starter

Start at the keyswitch with it held in the start position. Is there 12vdc on A1, S, B?

 

[The Cobbler]

you could have issues at multiple places, but a bad connection would be my first attempt at diagnosing. to start with I would check for voltage at the ign switch , then after the switch , then move on. above poster beat me to it

 

[Poolshark314]

Start at the keyswitch with it held in the start position. Is there 12vdc on A1, S, B?

you could have issues at multiple places, but a bad connection would be my first attempt at diagnosing. to start with I would check for voltage at the ign switch , then after the switch , then move on. above poster beat me to it

No power at the ignition at all, so started tracing the wires and found 2 fuses hidden bundled up and tied under the frame. A 20Amp fuse is blown in one of the holders. Hopefully that is the issue, once I get a chance to go grab a replacement fuse. Thank you for the super quick help everyone. This forum is so great!

 

[whateg01]

Starting the timer for when you come back that the replacement fuse blew

 

[Poolshark314]

Starting the timer for when you come back that the replacement fuse blew

Fuse didn't blow, but not out of the woods yet. Replacing the fuse got the hour meter working again. Getting 12v at the ignition switch, but no cranking still. On the starter solenoid, I get 12v on the battery side, but nothing on starter side while cranking

 

[dscheidt]

Do you have voltage in the operating terminal of the starter solenoid when the key is in crank? If not, I’d be looking for a broken wire, probably where harnesses go through holes, etc, where it could get cut or rubbed through. Broken wire is consistent with sudden stop, and blown fuse.

 

[The Cobbler]

I get 12v on the battery side, but nothing on starter side while cranking

what about the small sense wire, does that get voltage with the key in start position?

 

[Bill Bowman]

Is it possible that the mower deck switch is in the on position?

 

[larry_g]

Running out of ideas on what the issue is. Was mowing my yard with a Husqvarna MZ52 that I have had about 8 years and it shut off in the middle of mowing.

• Replaced the starter solenoid. I verified I have 12.6v at the battery side of the solenoid still. I can jump the starter relay and the motor will crank, so the starter itself is good, but it still won't turn all the way over

What do you mean by it won't turn all the way over? Is it hitting something hard stopping the crank from making a full two revolutions? Describe the moment it shut off, any BANG noises or did it act like you just shut the key off?

lg

 

[gmcgeo]

Seat pressure switch, or the brake is not engaging, and or the pto switch is on or stuck on.

 

[Poolshark314]

What do you mean by it won't turn all the way over? Is it hitting something hard stopping the crank from making a full two revolutions? Describe the moment it shut off, any BANG noises or did it act like you just shut the key off?

lg

It will crank if I jump the solenoid, but motor wouldn't fully start and stay running. I suspect that may have been related to the blown fuse, but have not attempted since I replaced the fuse.

When I get a chance, I'll try to test continuity on all the wires

 

[Poolshark314]

Checked continuity on the wires and one of the connectors had gotten a little loose. reseated and it fires right up now. Thank you all for the help!

 

[larry4406]

Wife’s Ferris zero turn has what I will call a “Molex type” connector with like 5-6 conductors in it. It has a lock for fully engage that snaps into place.

Nope. No conductivity and would not start.

Cleaned the pins all out, put back together and fully engaged the connectors till it snapped in place. I then ran a zip tie and used the zip tie gun to ensure its tight.

Has not failed to start since.

 

[Snapped-off]

I worked in a POS Toro that had a failed relay. It was just a typical 5 pin automotive relay.

 

[ScaldedDog]

I'm not sure if the Husky's are the same, but my John Deere has all kinds of "safety" switches built in. One of them keeps the mower from starting if the handles aren't out in the out (egress) position. That sounds fine, but it's not uncommon for debris - pine cones, in particular - to fall into the open space when the handles are in the inner (run) position. Push the handles out to stop for lunch, and come back to a mower that won't start. Troubleshoot for an hour, and then notice the crushed pinecone. Don't ask me how I know this...

Mark

 

[andyvh1959]

I had a lawn tractor that was hit/miss starting. Some times it would crank, most often not. I replaced the starter, solenoid, ignition switch, battery, positive cable, cleaned all the connections, still mostly miss. Then I took off the ground cable, checked for continuity, open. Bend the wire, continuity, bend it, open. Somewhere midpoint of the ground cable it had broken with no obvious outer damage. Had I 1st checked the cable I would avoided all the other stuff, so don't overlook the simple basics.