Briggs motor swap / Charging system differences

vtrwillie

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Hey Guys,
I just recently replaced an old briggs engine (Model 31A607) 15.5hp with a 17hp engine and have a issue with the differences in the charging systems. Below are pics showing the old engine wiring compared to the new. Where do I run the red wire that has the connector? (I think that's for the headlights?) and the yellow and orange plug?

Thanks
 

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keakar

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you went from an engine with a constant charging system to one that has a voltage regulator for charge on demand only

that red wire connects to the battery to read battery voltage to tell the regulator when to allow the engine to sent charging current to the battery. with that said i thing it needs to run through the key switch as well so there is no constant power bleed when the engine is off but im not 100% on that

i suggest you pull the flywheel off and swap out the alternator rings under it and remove that voltage regulator from the engine so you retain your original charging system setup
 

vtrwillie

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Can I switch the old setup to use the regulator on the new engine?
 

bertsmobile1

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Yes it is a direct swap
Then sell the new alternator.
 

vtrwillie

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Guess my post was a bit misleading, I would like to utilize the new charging system with the old wiring. Is there a way to accomplish that without having to do a ton of rewiring?
 

StarTech

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Okay the wire you are calling orange is most likely a fade red wire. This is connect the DC ouput (Red Wire) to. Depending if your light is switch or not determines if you just jumper to Yellow or not. The original wiring is for AC to the lights that is normally on all the time while the engine was running. A SPST switch must be added as part of the jumper so the lights can turned off or a wire added from the ignition switch to Yellow so when you turn off the mower you turn off the lights as well. Another option is just forget about having lights, on most mowers they pretty useless anyway.
 

keakar

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Guess my post was a bit misleading, I would like to utilize the new charging system with the old wiring. Is there a way to accomplish that without having to do a ton of rewiring?
no, if your mower isnt wired for a regulator on the existing original engine then its not an easy thing and requires rewiring the mower

as i mentioned, remove flywheel from old engine an new engines then swap your old alternator over to the new engine. the wires you need will be already attached to it and so you just plug it in and then go cut grass or drink a beer
 

StarTech

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no, if your mower isnt wired for a regulator on the existing original engine then its not an easy thing and requires rewiring the mower

as i mentioned, remove flywheel from old engine an new engines then swap your old alternator over to the new engine. the wires you need will be already attached to it and so you just plug it in and then go cut grass or drink a beer
It doesn't take swapping the old stator out with the new one. It is a simple matter connecting up as I describe in post #6. Come on don't make hard someone to simply hook one wire into pulling the flywheel, changing out the stator, and removing the voltage regulator.

I have done this kinda work for over 40 yrs. The only real change is the lighting circuit and as I said with most mowers the lighting is a joke.
 

StarTech

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While I am thinking about it keakar do you have any idea how to do a triple bypass on a JD Z925A ECU so that PTO and fuel solenoid operate but when PTO switch is on so that the engine does not engage the starter? I don't mean just replace the ECU. I have already done two this Spring. I don't see any reason to spend up to $200 for a new ECU when $10 in parts will fix the problem.
 

keakar

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It doesn't take swapping the old stator out with the new one. It is a simple matter connecting up as I describe in post #6. Come on don't make hard someone to simply hook one wire into pulling the flywheel, changing out the stator, and removing the voltage regulator.

I have done this kinda work for over 40 yrs. The only real change is the lighting circuit and as I said with most mowers the lighting is a joke.
well genius you forgot one thing, he wanted to know how to make the voltage regulator still work. its still not gonna function to charge the battery or put out any power until you get switched battery power to that red wire from the regulator and your installing relays is bypassing the regulator.

i dont like to "rig" things, i prefer to repair things back to the original design rather then "making things work"

in half the time it takes you to rig up relays and switches to make it work i have already replaced, swapped out, the alternators in 5 minutesand nothing needs to be rigged
 
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