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Curtis B.
Curtis B., Technician
Category: Small Engine
Satisfied Customers: 12592
Experience:  have worked on and around most engine models for 35 yrs./Polaris ATV expert
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I have a husqvarna mz6128 with Briggs and stratton engine

Customer Question

I have a husqvarna mz6128 with Briggs and stratton engine
mower only turns over with spark with brake safety switch barely push in in my hand.
tried 3 new brake switches same issue.
Submitted: 1 month ago.
Category: Small Engine
Expert:  Bill McCusker replied 1 month ago.

Hello my name is***** will do what i can to asset you.

To understand the mower only turns over with the brake saftey switch engaged. Did you remove the brake saftey switch? is that why you have it in the hand?

Customer: replied 1 month ago.
No it was plugged in did not work pushed all the way in or out only when I barely touched it ,. and it only fired barely touched on the brake safety switch .Brake switch should work all the way out or push inWhy is it working only barely touched and I'm using spark testers to see when it has spark
Expert:  Bill McCusker replied 1 month ago.

So when you barley push in the brake saftey switch you get spark to have the unit run??

If so the reason the engine doesnt spark is because one of the other saftey switches not working.. Some of the other switches is a seat switch.. If the switch is no good the mower dosnt know there is a operator.

Customer: replied 1 month ago.
I check the other safety switches and also replace them w news ones
Expert:  Bill McCusker replied 1 month ago.

ok let me pull up a wire diagram.

Expert:  Bill McCusker replied 1 month ago.

what saftey switches did you replace? brake, seat, pto, and the two switches at the arms..

Customer: replied 1 month ago.
Replaced all of them brake, seat, pto & 2 switches at armTried more than one new safety switch for each
Expert:  Bill McCusker replied 1 month ago.

here is a wire diagram.

i hope this helps..

Expert:  Bill McCusker replied 1 month ago.

ok.. Let me do some more checking in a service manual. i will get back to you

Customer: replied 1 month ago.
I already had wiring diagramI tried to locate service manual for this model & couldn't find one
Customer: replied 1 month ago.
If you couldn't find out anything else let me know so can see if someone else knowsthanks
Expert:  Bill McCusker replied 1 month ago.

Sorry its been a busy day.. have you checked the relays?

Expert:  Bill McCusker replied 1 month ago.

if all is well then i will opt out cause i have checked what the service manual have said. wish u good luck..

Expert:  Donald replied 1 month ago.

Hello. Thank you for choosing Just Answer. My name is***** you are still in need of assistance, please let me know. I will be happy to work with you, to help figure out what is causing our problem.

Customer: replied 1 month ago.
Expert:  Donald replied 1 month ago.

Thanks for your reply. Can you give me just a minute or two to mark your wiring diagram?

Expert:  Donald replied 1 month ago.

please take a look at the wiring diagram below.

Expert:  Donald replied 1 month ago.

There is a part labeled Timer in the diagram. If this timer is not opening, when your seat is occupied, ground will originate at your Timer, via your Brown Wire, then through your Green Wire, and over to your Brake Switch.

Expert:  Donald replied 1 month ago.

Notice the White Jumper Wire. This wire goes directly from your brake switch, to the ignition coil on your engine. This is your kill wire. So, regardless if your Parking Brake is "on" or "off", your engine spark will be restricted if either your Seat Safety Switch, your Seat Safety Switch wiring connector, or your Timer has failed. Keep in mind that your kill circuit originates at your Seat Switch, via the Black Wire.

Expert:  Donald replied 1 month ago.

Process of elimination. You have already replaced your Seat Safety Switch, so we can assume that it is ok. This leaves your Seat Safety Switch wiring connector, and your Timer.

Expert:  Donald replied 1 month ago.

You and I can continue from here. Thanks again!

Customer: replied 1 month ago.
I also ordered & replaced the timer too
Expert:  Donald replied 1 month ago.

Thanks for this additional information. There is a Purple wire going into your timer. Check to see if your Purple wire has 12 volts when your ignition switch is in the on position.

Expert:  Donald replied 1 month ago.

Do you have a multimeter, or a way to check for continuity? If so, check to see if you have continuity between the (M) terminal, and your (G) terminal, on your ignition switch, with your ignition switch in on position. Remove the wiring connector from your ignition switch, when checking this. Check this after checking for voltage on your Purple wire.

Expert:  Donald replied 1 month ago.

See Diagram Below ...

Expert:  Donald replied 1 month ago.

Let me know what your results are, and we can continue from here.