Ok guys. Heres a hard one. I picked up a craftsman lawn tractor model 917272201 with the 25hp Vanguard Engine. The guy told me that the engine will die when engaging the PTO switch, so he plugged the pto into the headlight switch to cut his grass. I assumed the safety switch under the seat was bad, so i replaced it. I discovered he had unplugged the switch under the seat. When i plugged the switch in, i attempted to move forward and the engine shut off. Even when i put a new switch in, it still died when attempting to engage the transmission. I swapped the pto switch and swapped the connector back to the original place its supposed to go. Try to engage the pto, the engine dies. But if i swap it back to the headlight plug and turn the key to the headlights, the pto engages just fine. No bogging ot anything so i know its an electrical problem somewhere. So right now, seat switch is unplugged, and pto is plugged into the headlight plug. Where in the heck do i start? Its a 46 in deck. Pulleys and spindles are fine. No binding.. ideas please!!
Craftsman Model 917272201
AAalsatropine
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Ok guys. Heres a hard one. I picked up a craftsman lawn tractor model 917272201 with the 25hp Vanguard Engine. The guy told me that the engine will die when engaging the PTO switch, so he plugged the pto into the headlight switch to cut his grass. I assumed the safety switch under the seat was bad, so i replaced it. I discovered he had unplugged the switch under the seat. When i plugged the switch in, i attempted to move forward and the engine shut off. Even when i put a new switch in, it still died when attempting to engage the transmission. I swapped the pto switch and swapped the connector back to the original place its supposed to go. Try to engage the pto, the engine dies. But if i swap it back to the headlight plug and turn the key to the headlights, the pto engages just fine. No bogging ot anything so i know its an electrical problem somewhere. So right now, seat switch is unplugged, and pto is plugged into the headlight plug. Where in the heck do i start? Its a 46 in deck. Pulleys and spindles are fine. No binding.. ideas please!!
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The seat switch plug may have a shorting feature in it, so unplugging it defeats your purpose. The connector needs to be on the switch to function. Check to see that the switch itself is being actuated, and that the switch is good. If you have the schematic, look closely for wording that indicates a shorting-type connector for the seat switch.
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2,132 Posts
The seat safety switch engages the operator present relay and the pto clutch is enabled by that relay. The relay may be bad or the plug may be corroded or dirty. The seat switch does not show a shorting type connector but the relay kind of takes the place of it.
The engine will stop if the pto switch is on when trying to engage the clutch.
The electrical schematic for your machine is below.
The engine will stop if the pto switch is on when trying to engage the clutch.
The electrical schematic for your machine is below.
Attachments
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Ive been studying this schematic like a hawk. The relay being bad is one idea ive pondered on. I have about a hundred relays at the shop, so im going to match one up and try it. Its had me stumped for a few days. I got the mower dirt cheap ( it was smoking) so the guy attempted to fix it himself and gave up. I got the smoking issue stopped ( number 1 cylinder head gasket and on number 2 cylinder he forgot to reinstall one of the pushrods ) so now i was working on electrical issues. Ill replace the relay when i get to the shop ( side job ) and see if that fixes it. I suspected the relay when two issues arose even after swapping out the PTO switch and seat switch and the issues were still there. Its hard to follow schematics when the diagram has wires crossing everywhere and no way to really follow them. SMH
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VTX , that schematic diagram is alot easier to follow. The one from sears is a nightmare. Thanks a million!
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These relays are very common automotive types and are used for lighting and power circuits on motorcycles. As long as it fits the socket and the diagram of the innards match, it should work. Hope a new relay solves your problem.
https://www.amazon.com/Stens-430-300-Assembly-Replaces-Husqvarna/dp/B001OK6OVY
https://www.amazon.com/Stens-430-300-Assembly-Replaces-Husqvarna/dp/B001OK6OVY
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Yea, thats why i have a ton of them at the shop. Every car or truck we disassemble at the shop, i keep everything as far as fuses, relays, switches, bulbs, ect. The costs of those things have skyrocketed in the last 5 years. I mean come on, a box of 5 fuses is like 4 bucks. Thats ridiculous.. a relay is around 10 bucks depending on what kind... no reason to throw away good parts lol
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With the key ON, but not running-
Manipulating the seat switch should make the OPR click ON/OFF......
Manipulating the seat switch should make the OPR click ON/OFF......
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You are correct Mr. Bill K. and now that you mention it, i didnt hear the click... might be on to something. Sad thing is, im certified as an EVT with one of my sub certifications in electrical and emergency lighting systems.. i think i need a vacation...
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As a test, you can also simply remove the OPR.
The PTO won't engage, but the engine shouldn't kill either.
It could simply be a bad connection in the OPR/OPR plug.
BTW- If your tractor has a Vanguard, the engine has been swapped.
The PTO won't engage, but the engine shouldn't kill either.
It could simply be a bad connection in the OPR/OPR plug.
BTW- If your tractor has a Vanguard, the engine has been swapped.
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Bill, i have the OPR switch removed and the engine atays running. As soon as i pull the PTO switch when it is connected correctly it kills the engine. The deck is connected to the headlight switch at the moment. When i turn the key to the headlights it engages the deck no problem. But when swapped over to the actual pto switch and i pull the pro switch it kills the engine. Thats why i was thinking relay
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Also i was referring to the wrong engine. Its a 25hp briggs twin cylinder. 445777-0129
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Nevermind, i thought you were referring to the switch, you are talking about removing the relay. Ill do that when i get to the shop
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Ok guys, its not the relay, Operator Presence Switch, or the PTO switch. I tested the safety interlock switch and both sides read 0 when checking for continuity. One side on the switch reads 0 when not activated, other side reads 0 when activated. PTO still engages when plugged into the headlight switch, kills the engine when plugged into the actual PTO plug. Im stumped...
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2,132 Posts
We will continue to troubleshoot with you. Did you do the tests Bill posted in #8 an #10? What were the results?
Looking closely at the schematic. The PTO switch is engaged and the engine dies. That means the black kill wire is being grounded somewhere other than the key switch.
There are two circuits that will ground the kill wire.
One goes through the clutch/brake safety switch to the relay and then to ground.
The other goes through the PTO switch terminals A and D. Then to the relay and to ground.
The seat switch has to engage the relay for the electric clutch can work and for the engine to keep running. All three switches interact with the relay.
If you remove the relay, does the engine stay running when the PTO switch is pulled?
The seat switch plug may damaged. Are your reading 12v on the green wire that goes to the relay? Reinstall the relay with the key switch on and the seat down. Does it click?
Looking closely at the schematic. The PTO switch is engaged and the engine dies. That means the black kill wire is being grounded somewhere other than the key switch.
There are two circuits that will ground the kill wire.
One goes through the clutch/brake safety switch to the relay and then to ground.
The other goes through the PTO switch terminals A and D. Then to the relay and to ground.
The seat switch has to engage the relay for the electric clutch can work and for the engine to keep running. All three switches interact with the relay.
If you remove the relay, does the engine stay running when the PTO switch is pulled?
The seat switch plug may damaged. Are your reading 12v on the green wire that goes to the relay? Reinstall the relay with the key switch on and the seat down. Does it click?
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Yes the engine stays running with the relay pulled. The switch under the seat tests good. I swapped it out with a new one just to make sure. With key on engine off the relay clicks when seat switch is activated.
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Yes it stays running
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Will do. Give me a few min. Jumped on another tractor to rebuild the carb for a guy...
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