My SuperBronco, 54" cut lawn tractor appears to have no power and won't start

cracker39

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  • / My SuperBronco, 54" cut lawn tractor appears to have no power and won't start
I started my Super Bronco lawn tractor this morning. It ran for a few seconds then the engine shut off. When the ignition is turned on, there is nothing. The hours used LED is off...blank...nada. I cleaned battery terminals and checked battery voltage, which is good. I can jump the starter and it operates. I do not know how to check the safety switches such as the ones for the seat and brake pedals. Any suggestions?
 

bertsmobile1

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  • / My SuperBronco, 54" cut lawn tractor appears to have no power and won't start
Start by locating the fuse.
It will be on a wire ( usually red ) connected to the battery cable on the solenoid ( saves wire ) then goes up to the key switch.
The wire(s) at the bottom of the solenoid are the trigger ( control ) wires .
All power for the mower except the PTO run through the single fuse .
If t blows strait away then pop back for more advice.
 

cracker39

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  • / My SuperBronco, 54" cut lawn tractor appears to have no power and won't start
I can find only one fuse, a blade type located at the battery. It is good. I checked continuity through the seat safety seitch. It has three wires. I cut the wires so i could check just the switch. When off the seat, there is continuity between all three wires. When the seat switch is depressed, no continuity between any two of the three wires. This seems odd to me. I would think that sitting on the seat would cause the switch to close an contact to be made through the wires, not the opposite. I cannot see any other fuses or safety switches, although I know that there must be one associated with the brake pedal. I need to see an electrical diagram, but haven't found one yet. And I am not sure how much it would help me if i had one.
 

bertsmobile1

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  • / My SuperBronco, 54" cut lawn tractor appears to have no power and won't start
That is why you need a circuit diagram
And we need one so we can tell you the pink& purple wire should show 12V then you are naked on the bonnet. :mad:
You will find it at the back of the parts book
To get the right parts book you need to use the model number off the tag under the seat.
IT will start with 13 or 14
We also need that number so we can also look up the right circuit diagram
As for the seat switch it is a Normally closed switch
If you take the plug out a hidden contact closes all wires together so you can not start nor run with the seat switch unplugged.
Thank the Face Book Fools & U-tube "heros" for that complication.

The red wire with the fuse in it will go up to the B terminal on the key switch ( B = Battery )
So the next step is to pull the plug off from behind the switch & check if you have 12 V there.
It is always best to pull the fuse out of the holder & replace it.
Blade fuses can look good even if they have blown.

Did you clean BOTH ends of the 2 battery cables ?
Most common fault is a loose or corroded ground connection .

The brake switch is either under the foot board or under the dash
The PTO switch is of course also under the dash
And that is all you have
Brake, Seat & PTO it is a simple system.
 

cracker39

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  • / My SuperBronco, 54" cut lawn tractor appears to have no power and won't start
Thanks for all the info. Early this morning, i disconnected the positive battery cable and will get a new one as the ole one is missing the connector that goes on the bolt at the battery. I disconnected the negative cable from the frame ground bolt and found everything clean, but sanded the contact areas anyway. I am also getting a new battery as the one i took out was dated 9/17 and shows some leakage around the positive terminal I did check the blade fuse with an ohm meter and it is good. With a new battery, new battery bolts, and a new positive cable, and everything reconnected, if it still doesn't show power on the hours display, with a friend's help i'll push it up onto my blade changing ramp where i can see beneath to try to locate the brake pedal interlock switch to check it. According to a parts diagram, that interlock switch is close to the brake pedal. Trying to remove the ignition switch is a last resort. I am thinking that dirty terminals, or even the battery, might be the problem Or, possibly the brake pedal interlock switch malfunctioning. All i do know is that power is not reaching the hours display so at this time, the starter is not an issue.
 

cracker39

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  • / My SuperBronco, 54" cut lawn tractor appears to have no power and won't start
The operation was a success. After attaching a new positive cable and cable bolts, cleaning contacts and installing a new battery, I turned the ignition key and saw data on the hours display. It started and ran and the PTO is working. Another simple fix, if you know what you're doing or have someone with more knowledge tell you what to do. Thanks again for the help.
 

bertsmobile1

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  • / My SuperBronco, 54" cut lawn tractor appears to have no power and won't start
Glad to hear that
I coat all bolted on connections with liquid electrical tape
It works very well to prevent galvanic corrosion .
When the mower is running check the battery voltage
IT should read at least 13 V
 
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