2003 Z Force 48” 53AA5A7M710 starts then dies

Newbie to the forum but not to a wrench but I still need some help.

Short version of the story I was gifted for a project a 2003 Z Force 48” model 53AA5A7M710 With the Briggs motor. When I got it, it had been sitting in a Kansas field for a while.

When I first got the motor running any time I touched (release) the break the motor would shut down so I got to work. Somehow I corrected the issue and the mower would drive, run, mow and basically do what it was supposed to.
Now after getting into even more I’ve replaced the starter, tires, PTO switch, oil, filter, fuel lines, fuel filter, bellcrank, clean/checked every switch and terminals and a battery. I’ve gone through every safety switch all wiring and connection and everything looked great.

Last night I took the mower out for it’s welcome back to life mow and it did good. So I pulled it into the garage. Now every time I turn the key it starts but dies when I release the break.

Now I would prefer to get the problem actually fixed instead of just checking all the connects again.
PLEASE HELP if you have a idea...

Thanks in advance RJ

If it dies when you try to engage blades also then more than likely it’s the seat switch.

MowLife said:

If it dies when you try to engage blades also then more than likely it’s the seat switch.

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It's not the seat switch. That has been tested. Dies when I disengage the parking break.

How did you test seat switch? Will the mower turn over if brake is disengaged and sitting in the seat?

MowLife said:

How did you test seat switch? Will the mower turn over if brake is disengaged and sitting in the seat?

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I tested the seat switch with a meter. It opens and closes like it should. I have 12v going to the switch. I’ve bypassed it to double check and it makes no difference. The motor dies when I touch anything. Starts just fine sitting in the seat, reach down flip the break lever to the “off” position and the motor dies.

The PTO is currently disconnected so that can’t be it. The PTO switch was replaced because the mower was running like it should for a 30 minutes but would not engage the deck. So I bypassed the pto clutch and got the deck working. The PTO clutch has 3.8 ohms so that is fine. Both operator switches work. Basically I think my options are. Break switch or relays. When the motor is off but key in the on position I can actuate the break switch and hear a relay click. Running out of ideas besides stripping it completely down and going through every wire and connectors again.

The Z forces use the safety switches to trigger relays so either the switch or the relay is causing you grief.
Remember the relay can be controlled from the power side or the ground side or both.
All of them are controlled by at least 2 switches

Download the owners manual and get a circuit diagram

Seat + brake is a single circuit so if the engine cuts out the instant the brake is released then seat switch is signaling the seat is unoccupied

So I re-tested the seat switch and with a meter it is opening and closing as it should. I ohmed out the relays, #1 &2 79, #3 67, so three is lower but still good. The 1 line diagram I have shows the seat switch going to relay #3. While the break switch goes to relay #1 and the pto.

When faced with these problems I manually bypass the relays by jumping from the 30 to the 87 or 87a slots in the plugs
Also note that some of the relays also control other relays in a cascade .
The safety cut outs are parallel circuits.
Test for trigger signals at the relay plugs.
I like to use a test lamp rather than a meter because a wire that is broken at the crimp will test good with a meter when the engine is not running but when the vibrations from the engine kicks in they no longer make contact.
A test lamp puts a load on the circuit so a just touching wire can test open with a lamp but closed with a meter.

So it runs and mows again. I found a post from 2007 that said a guy just pulled a relay and everything worked fine because it disabled safety switches.
So I thought why not. I pulled relay #1 and wala she took off like a 16 year old pig. Needs some adjustments made to the drive controls but overall it worked.

Now comes the question. What did I disable????