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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

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

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

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

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?

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.

vtrwillie said:

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?

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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

keakar said:

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

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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.

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.

StarTech said:

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.

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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

Just forget it, I not going to explain it any further as everything is already in place and simply needs one wire connected unless lighting is needed. Where the heck did you read that I suggesting installing relays? I have posted no such thing. The only added items was a SPST switch and wiring with terminals for lighting which the switch may not even be needed as I haven't seen the equipment wiring schematic. Actually connector wise he need only two connector housings, a short section of insulated wire, and three terminals.

As for that JD I referred to there is not single added switch or relay. All it takes is less than two feet of wire and handful terminals and it is wire in a way that original setup can be simply restored later. 30 minutes to do (Counting printing a copy of the circuit schematic, getting and putting the tools up, the parts from storage, and the disassembly / reassembly of the equipment. It takes a minimum of two days to get the ECU plus driving two 45 minutes trips.

Are really taking only 5 minutes to get the tools, disassemble, remove and replace the stator plus voltage regulator, torquing everything to specs as you reassemble, test the new install, and put your tools back up. You must seen as just a blur. Even Briggs allows 45 minutes to do it on the 310000 series. On your time scale you should be able to do 300 engines in one my 10 hr days. Personally I doubt it.

StarTech said:

Are really taking only 5 minutes to get the tools, disassemble, remove and replace the stator plus voltage regulator, torquing everything to specs as you reassemble, test the new install, and put your tools back up. You must seen as just a blur. Even Briggs allows 45 minutes to do it on the 310000 series. On your time scale you should be able to do 300 engines in one my 10 hr days. Personally I doubt it.

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once the mower is in my shop and i have my tools ready, yes its a 5 minute job to pull the cover, flywheel, replace the alternator ring, reassemble and start the engine. any decent mechanic can.

if it takes you 45 minutes to do that then you are one sorry mechanic and you should be working at the DMV at the speed you work lol.

Well it does takes me a while to do the paperwork and other things so I QUIT. You can have all the galled blower housing screws. I mean it I QUIT. I am tired of being insulted. If I had the tools at the ready I also could it rather quickly. I hope you just charging the customer for 5 minutes instead of a minimum hourly rate.

Interesting.
I charge out work according to the prescribed rates for warranty work as being realtively new I am not the fastest mechanic in town.
When I add of the steps in the Stihl scheduled fee chart I have an alternator replacement comes in at 1 hour 13 minutes ( which would be for a Murray Viking ) including diagnosis time
Tecumseh allow 60 minutes for an alternator/stator replacement and they were not renown for being generous with warranty repair payments and that time does not include things like diagnosis or preparing the mower.
All the other scheduled service rate tables I have are for hand held tools so that is all I have to go by.

What I fail to see is how the amount of time taken to do the job makes any difference to VTRWILLIE fixing his mower.
He is a home owner & not an experienced technician so it will probably take him the better part of a whole day.
Heck I can take 10 minutes just to get that moungrel plug apart.
Off topic argueing between ourselves does no good for the forum, the readers or the parties argueing themselves.

sorry for starting a shitstorm! Just looking on how to get the wiring hooked up correctly with hopes of using the regulator on the new motor.

Not your problem
The train can run off the rails from time to time.
The important thing is how is your mower ?

true! Its running and cutting grass, albeit the charging system is not hooked up

If you can get through a days mow without running the battery flat then you can just charge the battery when you finish
If the connections are giving you grief then come back .
The instructions Star gave you will work quite fine.

vtrwillie said:

true! Its running and cutting grass, albeit the charging system is not hooked up

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well its a simple matter to put it back in original condition to charge the battery. if you dont you will ruin your battery in short order and those battery dont last very long if you dont keep draining them down.

all you need in an impact gun to remove the flywheel bolt or nut and a 1/4" nut driver and a few minutes of your time. the process is the same even though the engine style in the video is old version engines, this is what the alternator (skip to time stamp 3:00 to get past the silly comedy bits that start off all his videos)
also an added note about the wires, he mentioned they go behind the starter but on newer engines they dont, they have a bracket on the starter bolt that holds the wires on the outside edge of the starter bracket

keakar said:

well its a simple matter to put it back in original condition to charge the battery. if you dont you will ruin your battery in short order and those battery dont last very long if you dont keep draining them down.

all you need in an impact gun to remove the flywheel bolt or nut and a 1/4" nut driver and a few minutes of your time. the process is the same even though the engine style in the video is old version engines, this is what the alternator (skip to time stamp 3:00 to get past the silly comedy bits that start off all his videos)

also an added note about the wires, he mentioned they go behind the starter but on newer engines they dont, they have a bracket on the starter bolt that holds the wires on the outside edge of the starter bracket

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You might need to find out what engine he has along with the datecode so the correct info from the two APSIs on 21, 28, 31, 330000 series is given if required. Also there is a new torque spec if it is a 21, 28, 31, 330000 series.

StarTech said:

You might need to find out what engine he has along with the datecode so the correct info from the two APSIs on 21, 28, 31, 330000 series is given if required. Also there is a new torque spec if it is a 21, 28, 31, 330000 series.

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hes not grabbing random parts from a junk yard, he would be using the oem charging system that came with the mower, so its an exact perfect matched system

if he wasnt using the oem parts from the original engine i wouldnt be suggesting he use them without checking the specs

Apparently you do not know (or care) there were changes from using an aluminum flywheel key to two different steel keys depending flywheel and crankshaft design on the fore mention series and a new torque spec for tightening the flywheel retainer. IF the OP is working one of the series listed then the associated Briggs APSIs needs to be applied. The engine may already have these applied but it still need to checked to be sure and upgraded if not.

Maybe you one those that just tighten the flywheel retainer with an impact and call it done.

StarTech said:

The engine may already have these applied but it still need to checked to be sure and upgraded if not.

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i agree with this ^^^^^