Kohler to Briggs wiring issue

   / Kohler to Briggs wiring issue #1  

DLinMI

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I've swapped a Briggs into my Cub Cadet XT1 which had blown the original Kohler Courage 18hp engine. The Briggs is out of a Craftsman riding mower, it's a 15.5HP Turbo Cool model 28U707. It starts and runs but the fuse at the + battery post is blowing, so will not start again untill the fuse is replaced. So apparently I've got something wrong. The original wiring on the Kohler had the violet wire running to a "rectifier-regulator" which then had the two wires from the stator connected to it. The only other wires on the engine side that were connected were the fuel solonoid on the carb and the ignition module. The Craftsman with the Briggs had 4 wires on the engine side, the same fuel and ignition connections, but the wires from the stator went back into the harness back to the ignition switch. This is where I believe my error is. According to the Briggs schematic, there is an orange and red wire coming from the "alternator/stator", the red with a diode inline that reads charging system output 3 amp DC. Supposedly an orange wire that is labeled, " lighting system output 5 amp AC @ 3600 rpm/ 14 volts AC min @ 3600 rpm (lights off), but I have a red and BLACK wire coming from the stator. When the Briggs is plugged into the Craftsman harness the red wire from the stator is connected to an orange wire going back to the ignition. So my "guess" was to connect my violet wire to the red wire with the diode inline. I'm now assuming that was wrong. I did not visually verify if there was a diode and which wire it was on, only went by schematic. Tried to remove flywheel but wasn't having any luck. Tried to attach the schematics, but couldn't figure out how, kept getting a "file too large" message. I can't seem to be able to find any "Help" section on this forum.
 
   / Kohler to Briggs wiring issue #2  

tomplum

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It sounds like to me that the new engine has the dual circuit alternator. The red with the diode is DC for the battery and the black AC lighting.
I'm not sure what ignition the Kohler engine had. If it were a twin, it is possible that you had battery voltage heading to the coil. With the Briggs , that will kill the coil- so make sure you know what you have at that wire.
 
   / Kohler to Briggs wiring issue
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#3  
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DLinMI

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Both engines are single cylinder. According to the schematic the black wire is exactly as you say, AC lighting output, but I did not attach it to anything, it's still in the connector unattached. I should mention that I had to replace the starter, when I went to hook up the power on the original the mounting stud fell right out. Also, when I did have the mower running I went to get off of it and it died, which would only happen on the original unit as a safety feature when the deck was engaged. So I don't know what is going on there. With a new fuse the engine will start and run fine, but apparently the charging system or something else blows the fuse, after shutting off the fuse is blown and has to be replaced????
 
   / Kohler to Briggs wiring issue
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#4  
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DLinMI

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Here are the schematics
20230506_115235.jpg
20230506_115209.jpg
 
   / Kohler to Briggs wiring issue #5  

tomplum

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The engine should stay running once the park brake is set / deck off. Didn't pinch a wire behind the starter maybe? The AC wire wouldn't be used if your lights are run off the DC to switch.
 
   / Kohler to Briggs wiring issue
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DLinMI

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Well, I was going to check the voltage coming from the stator while running, so I put in a new fuse and before I got it started I noticed smoke coming from under the flywheel. Pulled the fuse and tore it down to get a look at the alternator/stator. And found my error. When I connected the violet wire from the Kohler to the red from the Briggs I had to cut the red wire from the harness connector of the Briggs because the pin wouldn't work in the Kohler connector so I hard wired the violet to the red. Unknown to me, the diode was right at the connector and I cut just above it and leaving it out of my connection!! I had assumed the diode was inline up under the flywheel where I couldn't see it. So I have a stator coming tomorrow, this one had started to melt and I have zero confidence in being able to solder the diode back to the red wire. I assume the burning and or melting was from the 12 volt from the battery back feeding to the stator, does the inline diode prevent this as well? Thanks
 
   / Kohler to Briggs wiring issue #7  

tomplum

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The diode is a one way valve so to speak. It's always somethin'...
 
   / Kohler to Briggs wiring issue
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DLinMI

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Installed new stator, wired it "correctly " and all is well so far, thanks.
 
   / Kohler to Briggs wiring issue #9  

Richard001

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Well, I was going to check the voltage coming from the stator while running, so I put in a new fuse and before I got it started I noticed smoke coming from under the flywheel. Pulled the fuse and tore it down to get a look at the alternator/stator. And found my error. When I connected the violet wire from the Kohler to the red from the Briggs I had to cut the red wire from the harness connector of the Briggs because the pin wouldn't work in the Kohler connector so I hard wired the violet to the red. Unknown to me, the diode was right at the connector and I cut just above it and leaving it out of my connection!! I had assumed the diode was inline up under the flywheel where I couldn't see it. So I have a stator coming tomorrow, this one had started to melt and I have zero confidence in being able to solder the diode back to the red wire. I assume the burning and or melting was from the 12 volt from the battery back feeding to the stator, does the inline diode prevent this as well? Thanks

Yep, that's that way it goes. When the smoke leaks out, it stops working. Everyone knows that electronics work by smoke, and when it's gone, then nothing works.

Also you should note that any wire cut to length will be too short.

Richard
 
 
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