Mower Blows 20 amp fuse when PTO when PTO is engaged
- Thread starter JeffNC
- Start date
Good Lord I gotta say...this forum and participants are not only fantastic, but very impressive and generous. I want to thank each of you for taking your precious time to reply to my thread! I'm not at the expert level that you guys are so please overlook that of me. That said, I've done the following in addition to actions taken in my initial post:
1) Replaced Fuse Holder,
2) Replaced Battery Cables,
3) Replaced Battery (my fault, I broke a corroded terminal),
4) My second mower repair guy has not been able to fix this 20 amp fuse blowing issue:
1st Repairman: You need a new PTO Clutch, short in clutch, so purchased OEM Briggs and Stratton PTO Clutch for $250, same result.
2nd Repairman: All is well with blades cutting until about 10 minutes, then blows fuse. Told me that my PTO clutch was hot to the touch so was the cause of blowing 20 amp fuse. The real issue I see is...difficult to troulbleshoot since fuse does not blow or no issues at all, until afgter 10 minutes of cutting grass, then blades stop, and engine still runs,,,
I'm actually thinking that these 2 repairmen are 'shade tree' repairmen and do not know how to troubleshoot electrical grounds (ie troubleshooting like: if ignition switch is in one position, there is a short in 1 circuit or if ignition switch is in another position, its this circuit) and while I'm no expert either. I hate to consider the cost of a new mower when I feel as if there might be a simple fix.....everything is fantastic while the fuse does not blow...engine runs fantastic!! Thanks again you guys! Y'all so gracious and generous with your time on my behalf!! Thank you!!
1) Replaced Fuse Holder,
2) Replaced Battery Cables,
3) Replaced Battery (my fault, I broke a corroded terminal),
4) My second mower repair guy has not been able to fix this 20 amp fuse blowing issue:
1st Repairman: You need a new PTO Clutch, short in clutch, so purchased OEM Briggs and Stratton PTO Clutch for $250, same result.
2nd Repairman: All is well with blades cutting until about 10 minutes, then blows fuse. Told me that my PTO clutch was hot to the touch so was the cause of blowing 20 amp fuse. The real issue I see is...difficult to troulbleshoot since fuse does not blow or no issues at all, until afgter 10 minutes of cutting grass, then blades stop, and engine still runs,,,
I'm actually thinking that these 2 repairmen are 'shade tree' repairmen and do not know how to troubleshoot electrical grounds (ie troubleshooting like: if ignition switch is in one position, there is a short in 1 circuit or if ignition switch is in another position, its this circuit) and while I'm no expert either. I hate to consider the cost of a new mower when I feel as if there might be a simple fix.....everything is fantastic while the fuse does not blow...engine runs fantastic!! Thanks again you guys! Y'all so gracious and generous with your time on my behalf!! Thank you!!
Jeff:
It sure seems like it is an intermittent short. This is one of those where you need to trace the positive 12 volt wire coming off the downstream side of the fuse and physically examine the wire for worn insulation, or evidence of it shorting to the chassis somewhere as Ilengine suggested. Keep in mind that anything or wire on the downstream side of the fuse can be causing the problem so you have to examine them all carefully. Focus on any point where a wire(s) is next to the frame or a bracket. It's highly unlikely that it's part of the coil inside the PTO. If it was, it is unlikely it would work again when you replaced the fuse.
Another "static" test is to turn it on, but don't start it. Turn on the PTO with a fresh fuse and see if it still blows after a few minutes without the vibration or movement from the engine running or mowing. I'm attaching a link to a nice troubleshooting guide for garden tractor clutches made by Warner Electric. Makes for great bathroom reading! More than you probably want to know about a PTO. FYI...
https://www.altraliterature.com/-/m...ner-electric/service-manuals/p-1097-6-we.ashx
Kelly
It sure seems like it is an intermittent short. This is one of those where you need to trace the positive 12 volt wire coming off the downstream side of the fuse and physically examine the wire for worn insulation, or evidence of it shorting to the chassis somewhere as Ilengine suggested. Keep in mind that anything or wire on the downstream side of the fuse can be causing the problem so you have to examine them all carefully. Focus on any point where a wire(s) is next to the frame or a bracket. It's highly unlikely that it's part of the coil inside the PTO. If it was, it is unlikely it would work again when you replaced the fuse.
Another "static" test is to turn it on, but don't start it. Turn on the PTO with a fresh fuse and see if it still blows after a few minutes without the vibration or movement from the engine running or mowing. I'm attaching a link to a nice troubleshooting guide for garden tractor clutches made by Warner Electric. Makes for great bathroom reading! More than you probably want to know about a PTO. FYI...
https://www.altraliterature.com/-/m...ner-electric/service-manuals/p-1097-6-we.ashx
Kelly
Jeff, if you are referring to the starter solenoid, the answer is no. The only time power is applied to the solenoid coil is when the key switch is in the start position, not while it's in the run position.
Do you have a wiring diagram for the machine? Is there one online(I didn't see your model number anywhere in this thread)? Let us know the which model Simplicity you have. Can probably give better advice knowing the exact machine you have and locating a wiring diagram.
Do you have a wiring diagram for the machine? Is there one online(I didn't see your model number anywhere in this thread)? Let us know the which model Simplicity you have. Can probably give better advice knowing the exact machine you have and locating a wiring diagram.
I really appreciate all that you guys are doing to assist me! Great website! The model number and description is:
2690574 - Simplicity Regent Lawn Tractor, 44" Deck, 20HP Kohler Hydro RMO. I've attached an electrical diagram to this post. Might there be a troubleshooting procedure that I could follow for this wiring diagram, as I performed your static test with a new fuse and the fuse never did blow after at least 15 minutes...sounds like an intermittent wiring short when mower is operating or moving (UGH)?......thanks very much!
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bertsmobile1
Lawn Royalty
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That is a loom, not a wiring diagram .
Take the hood off and run the mower somewhere very dark
Look around the rectifier for sparking.
You can also disconnect the rectifier and see if the mower blows the fuse again.
With no power from the alternator you should get around 2 to 4 hours of mowing from a fully charged battery.
If the fuse does not blow with the alternator not connected then your problem is with the rectifier and the usual problem is a broken ground wire.
Take the hood off and run the mower somewhere very dark
Look around the rectifier for sparking.
You can also disconnect the rectifier and see if the mower blows the fuse again.
With no power from the alternator you should get around 2 to 4 hours of mowing from a fully charged battery.
If the fuse does not blow with the alternator not connected then your problem is with the rectifier and the usual problem is a broken ground wire.
Going to try to see sparking around rectifier while running at dark. Thinking since rectifier is located inside and under the flywheel, sparking may be difficult to notice, so will also try disconnecting rectifier as you suggested to see if it cuts grass without blowing a fuse for 2-4 hours. If so, I'll remove blower/flywheel to inspect ground wire to rectifier and also possibly replace rectifier. These are great ideas and much appreciated! Will keep yall posted!! Thx so much!
If you go to the Simplicity site, you can download the attached, which is the true wiring diagram you need for troubleshooting. It's at the bottom of the list of 11 results when you search their support site for the manual(s) for your unit. What you posted is a parts list page for the Electrical Group.
Refer to the Charging Circuit page and the PTO page. When the tractor is 'running' (as opposed to cranking or shutting off) the B, L, and A terminals of the ignition switch are connected together. [that's what the Ignition Switch table tells you at the top of the page] That means if you follow the wire from the 20A fuse, it goes to the B terminal. It connects to the L and A terminals from there. Note everywhere it goes, particularly that L goes to a tiepoint labeled "D" and several wires connect there.
What does all this mean? If ANY of those wires has an intermittent short to ground, the fuse will blow. That's because they are all connected together, and any one can be the culprit. Likely to be where a wire is near the metal frame and over time through vibration has worn away the insulation. For example, on the charging circuit page, the red/white wire could cause it. On the PTO page, it's not just the highlighted power wire to the PTO, but ANY wire that connects to point D.
Keep in mind, the diagram is the same on every page. They are just highlighting the specific circuits like Charging, Cranking, PTO, etc.
Take a look and see if this makes sense... Let us know what questions you might have.
Refer to the Charging Circuit page and the PTO page. When the tractor is 'running' (as opposed to cranking or shutting off) the B, L, and A terminals of the ignition switch are connected together. [that's what the Ignition Switch table tells you at the top of the page] That means if you follow the wire from the 20A fuse, it goes to the B terminal. It connects to the L and A terminals from there. Note everywhere it goes, particularly that L goes to a tiepoint labeled "D" and several wires connect there.
What does all this mean? If ANY of those wires has an intermittent short to ground, the fuse will blow. That's because they are all connected together, and any one can be the culprit. Likely to be where a wire is near the metal frame and over time through vibration has worn away the insulation. For example, on the charging circuit page, the red/white wire could cause it. On the PTO page, it's not just the highlighted power wire to the PTO, but ANY wire that connects to point D.
Keep in mind, the diagram is the same on every page. They are just highlighting the specific circuits like Charging, Cranking, PTO, etc.
Take a look and see if this makes sense... Let us know what questions you might have.