kohler command pro 25

[Luffydog]

this is the issue when you turn the key to the on postion it tries to start even with pto on and all the other safety switches disengaged.. any thoughts new wiring harness for the unit pto switch key switch tried new starter all new relays. thinking there is diodes in the kohler harness doing some funny back feeding to allow the blue wire to get hot with the key switch in the on position.. thanks for any ideas its a stumper!!!!!

[KE4AVB]

Wouldn't to know the mower model number that you working on.

Assumng DSAI and assuming you have a solenoid shift starter. Yes if the steering diode is shorted if on an older engine that previous operated correctly or if a brand new engine harness, a steering diode installed backwards.

The blue diamond would the suspected bad one; although, both may be bad as they are both steering diodes. Otherwords the setup is to allow +12 v to flow to the coils and not to back flow to the starter or other engine or mower systems. IF I got things straight in my mind the red wire going to coils is +12v hot when the switch is on.

[Luffydog]

Stc61v-25cv-fr is the model. Sorry all the engine numbers all missing. The starter solenoid is on the starter.

[Luffydog]

Ps-cv730-3112 I think is the engine numbers

[KE4AVB]

Stc61v-25cv-fr is the model. Sorry all the engine numbers all missing. The starter solenoid is on the starter.

Scag...Solenoid shift starter. Engine number given say its CDI ignition so the +12V only goes to carb fuel solenoid. Same wiring generally on the engine side with steering diodes.

Dark blue wire on the PTO switch goes directly to the PTO clutch. With the engine plug disconnected check the Green wire with white stripe to see if +12v is present in run mode. If present then something on the mower side has the starter relay active.

[Luffydog]

yes I do have 12v on the green white wire in the on pos.. and not in the crank pos..

[Luffydog]

just unhooked all the safteys switches the same thing and also unhooked the safety interlock mod same thing. only time it wot try to start in the on pos is when I unhook the yellow wire from the key switch.

[KE4AVB]

Something must wired wrong then or the key switch is shorted.

Here the circuit for the Scag. The A terminal is an accessory output line. The Kohler engine wiring side is the engine service manual.
http://www.scagoemparts.com/pages/oemparts#/Scag_Power_Equipment/STC61V-25CV-FR_(S%2f%2fN_E3300001-E3399999)/Electrical_Schematic/10%7c%7e43%7c%7e0035/10%7c%7e43%7c%7e0033

• Off = G M A
• On = B L A
• Start = B S L

[Luffydog]

Today I learnt and heard the real story on this mower. The man was mowing along and this unit shut down and stopped. He checked the fuses and they was blowed. He replaced the fuses and turned the key to the on pos. And this all started occurring. He then learnt the fuel shut off didn't have power so he ran a hot wire to the fuel shut off to get it to his shop and he couldn't fix it to where it wouldn't stop cranking over in the on pos. Then it came to me I knew how to fix the problem but didn't know what was the cause of the cranking issues. In the Kohler breakdown wiring harness it didn't show the diodes at least the one I had didn't but I knew it had a back feed from somewhere causing the issue. I first thought of diodes but I couldn't find them right off so I didn't think there was any in the harness. Many thanks to Ke4avb for giving me some guideness of find them. Not going to lie I was lost at the point where I was confusing myself in what to do next. Just wanted to say thanks again for what this site has done and the people who went out of the way and the extra mile to help. Special thanks to Ke4avb. Thanks again. problem solved the engine wiring harness failed.

[Luffydog]

Pm sent to Ke4avb