I'd suggest getting a mower battery that ISN'T junk for a start.

Are the charging systems compatible between the 2 engines, or did you do some "surgery" to the wiring?
Briggs has multiple versions of their charge systems, and it might be possible you are trying to charge the battery with AC or neg. DC???

Post the tractor 917.xxxxx number

well i can post the tractor number, but the original motor is not intact. it has been replaced by the 16.5 HP model no. I posted already. do you still want the tractor numbers? the original 917.?
as far as being compatible between the 2, i've never thought of that. the current battery is not up to par so i've been supplying the tractor juice through a jump to the batt. cables on the tractor from my car. the battery needs to be replaced or 'refreshed', but i can't find the caps needed to replace the drilled-out holes from the orig. battery. (haven't drilled them out yet)
I have not done anything to the wiring...yet. The solenoid gets 12V from my car battery to the first post, yet gets something like 190mv to the second post on the solenoid (that goes to the starter) and only 22 - 27 mv on the smaller links which I presume are battery ground and AC. I have no idea what they are supposed to get, but I thought when you turned the key to start, the big (other) post on the solenoid should get 12V too.?
Thank you for replying!!

Yes, the 917 number might give one a chance of getting a look at an online wiring diagram for the chassis. That diagram would show us how the original tractor wiring SHOULD have been configured.
After we know how it is supposed to be wired.........then we can set about determining if the engine "swappers" did something wrong that is messing up the works.

"...do you still want the tractor numbers? the original 917.?...."

Only if you still want help!

What is this, about drilling holes in the battery caps??? That statement alone is enough to scare away any help! This guy should just bite the bullet, and go buy a whole new machine, and leave the old one setting on the curb!
This method of repair would solve all of his problems, and he won't have to drill holes in the battery caps.
Some folks can be Doctors, some can sell news papers, some can be cooks, or mechanics, athletes, etc., but not all of those types can ever fix things. That is why things are made and sold to the population at large. And, thats why we get all of the questions on fixing things, and why somebody thinks they should drill holes in the battery caps! "The old battery had holes, but this one doesn't have them, so i think i'd better drill holes in the caps." BLBLBLBL! RJ

I think Rusty nailed it.

Walt Conner

The tractor model no. is 917.272140.

"What is this, about drilling holes in the battery caps??? That statement alone is enough to scare away any help!"

Haha, precisely why I am looking for assistance! I got the idea after searching online for how to refresh a battery. It worked with a car battery that had the pop-off tops for accessing the cells. I dissolved Epsom salts in distilled water and then added the solution, then charged, discharged the battery twice and recharged it and it tests fresh at 12.47V. With a sealed battery, there are pre-scored circles for the cells and then you plug the holes, like with a motorcycle battery. I'm trying to save the money for one, because I feel that if I spend the $50 and put the new battery in without figuring out what electrically is wrong then that battery may become junk and the process will just repeat itself. Once that is sorted out then I will replace the battery. I haven't been able to find the plugs anywhere, anyway. In the meantime for proper battery strength I have been jumping my car battery (not the 'refreshed' one) to the tractor battery or sometimes removing the tractor battery and jumping my car direct to the tractor battery cables. This machine is becoming a financial drain, but I am determined to get it to run properly!

Thank you all for the help!

The original engine (407777-0121-E1) had a 15 amp charging system.
You current engine has the "dual circuit" system.
It either produces 2-4 AMPs DC
OR
2-4 AMPs DC and 14V Ac for lights (which would require a separate light switch and "surgery" for your tractor), depending on the connector used.
Hardly enough to power an electric clutch, Operator Presence Relay, carb fuel solenoid and still charge the battery.
Use the headlights (without the cumshaw surgery) and you're really in a hole, charging wise.

The good news is that you can use the existing stator & Voltage regulator from the old engine.
Bad news is IF you don't have the old engine!

Fly wheel is IFFY. I believe the one for the higher output system has larger magnets?
Walt can probably chime in on that.

Using flywheel from original Dual Circuit System with Stater & Regulator from 15 amp system is going to yield about 9 amps, enough to do the job.

Walt Conner

Ugga. I don't have the old engine. The current engine was running fine when I got it until I tried cleaning the carb. It ran better after that, but then quit and wouldn't start and that's when all my problems came to light. At that point I removed the blower housing and found the spark plug wire chewed so I replaced the armature. At the time I didn't test the solenoid with a multimeter. The key switch wouldn't work so I just jumped the starter straight by bypassing it and it worked. The engine started, but it smoked (black) and sucked up a 1/4 tank of gas in less than 10 mins. and was surging and would sound like it was choking out until I would let out the clutch. Then it would rev back up to normal until I ran out of gas. Since then I haven't been able to start it even with bypassing the solenoid. I'm sure the adjustment screw needs to be turned to lean out the mixture, but I can't do that if it won't start. I don't want to keep bypassing the solenoid. How can it be re-wired to work? The lights never worked even though they test good and so do the wires. There also is a 20A fuse in the fuse holder. I'll replace it with a 15A since that was original even with a larger engine. Can I bypass the lights to get the extra 14V back? When it comes to the electrical I am almost at a loss knowledge-wise except for very basic testing. Thank you for the effort! It won't go unwasted!

Just don't turn on the lights and you can solve that problem.
IF it sucked a 1/4 tank of gas in 10 minutes, your carb needs to be redone.
The needle & seat is leaking.
Probably a piece of crud got washed down there when you reconnected the fuel line. All it takes is a tiny speck to get lodged there.

Have you actually charged the battery and had it load tested?

I'll assume your stator has a RED and a BLACK wire coming from it.
How do you have those connected and to WHAT?

Maybe you could put a want ad on Caigslist or something for a blown 31 series engine with the higher output charge system and scavenge the parts.

BTW, the schematic shows a 30 amp fuse.

So then is the lack of a voltage regulator what could be cooking the solenoids? The lights haven't been hooked up when it's been running.

It does have red and black from stator. Red ends with diode in 2 prong connector and black. That connects to a yellow and another red/yellow wire that feeds into a 6 prong connector that has 2 empty, the 2 yellows, a whitish, and black wire that plugs into yet another connector that now becomes orange, blue, black, and a red jumper. Back to the previous connector, the whitish goes to the fuel solenoid and black goes to armature.

***"So then is the lack of a voltage regulator what could be cooking the solenoids?"***
No, and we don't even know for certain that the solenoids are actually "fried".
I will try to post something tomorrow after looking at the OEM diagram.
I actually think you are being provided with good help already by bill and walt but you gotta read carefully what is being given to you in order to work it out.
Realize that the machine you now have is not a "pedigree" any longer. Trying to work out problems with "X-breeds" requires more understanding of the basics/fundamentals because it is often impossible to give instructions regarding specific wiring matches as the OEM scheme no longer applies.

"So then is the lack of a voltage regulator what could be cooking the solenoids?"
How? It's not charging when you are trying to start it.
You're probably cooking solenoids from extended use with a battery that can't do the job.

Have you tried charging the battery and having it load tested?
You're going to have to charge the battery before using it anyway, if you plan on keeping the 3 AMP charging system on a tractor that probably requires 4-5 AMPS to operate.
Trying to operate the PTO without enough voltage is going to ruin it. PTO engages, drops voltage so much that it disengages, voltage rises, PTO engages, voltage drops......

The RED wire from the stator, going through the diode is your DC output for battery charging etc.
The BLACK wire from the stator is AC for THOSE TRACTORS DESIGNED FOR THAT SYSTEM. In your case, you don't want it hooked to ANYTHING, at least for now.

The black wire to the armature is the kill wire which comes from the M terminal of the key switch.

I can't decipher the rest of your description. Sounds like everything hooks to everything.

LOOK AT THE SCHEMATIC. That will tell you much.

You really need the 696458 stator and 691185 voltage regulator.

Your gas consumption maybe caused by a weak spark due to an inadequate charging system compounded by a weak battery

"Your gas consumption maybe caused by a weak spark due to an inadequate charging system compounded by a weak battery"

NO, The charging system plus the battery and the ignition system are completely independent, or better be or the ignition system of this engine will be fried promptly.

Walt Conner

Let me work my way backwards...

"NO, The charging system plus the battery and the ignition system are completely independent, or better be or the ignition system of this engine will be fried promptly."

That is correct according to the schematic for the currently installed engine which is the B & S model no. 311707 0125 E1. Here is the quote from that schematic word-for-word... "Your tractor is equipped with a special alternator system. The lights are not connected to the battery, but have their own electrical source. Because of this, the brightness of the lights will change with engine speed. At idle the lights will dim. As the engine is speeded up, the lights will become their brightest."

"You're probably cooking solenoids from extended use with a battery that can't do the job."

The tractor battery is either jumped in series with a good car battery that is still in the car, or that tractor battery is removed and the car battery is jumped directly to the tractor battery's cables (in the tractor seat area).

BTW, the PTO isn't connected because the deck isn't connected. I didn't mention that in my first post and apologize. It is just the tractor frame, it's parts (clutch, hydro-tranny, starter, etc.), the electrical, and the current engine which started via key switch multiple times with no issue and then stopped (and continues to be stopped after mulitple solenoids). The deck is available, just not connected...yet!

"So then is the lack of a voltage regulator what could be cooking the solenoids?
How? It's not charging when you are trying to start it."

It charges fine after it is started becuause the dead battery won't die, however I have to jump it from my car neg. battery to neg. tractor batt. post (or clamp to neg. batt. connection if tractor batt. removed) and then BYPASS pos. batt. directly to starter. That will start engine and once running it goes and goes (well, unless tractor batt. is removed and then I can't drive it anywhere). But if tractor battery is in, it will go until fuel tank runs out!

"I can't decipher the rest of your description. Sounds like everything hooks to everything.'

It LOOKS like that too! But still, the thing would start right up no problem when I turned the key when I first got it. Now it won't start no matter what when I turn the key. No click from the solenoids, nothing. That's why i'm here!!

"Realize that the machine you now have is not a "pedigree" any longer."

It wasn't a pedigree to begin with. It ran, now it doesn't. I haven't changed anything to do with the wiring, only the parts I stated originally and now i'm at a loss because it 'lost' its original 'panache'!

I guess you have it all figured out then. BYE!

Using a volt meter and a GOOD battery:
Check that fuse is good.
Check Red wire at key switch for battery voltage.
No voltage, recheck fuse and inspect wiring between fuse and key switch.
If yes, has voltage, turn key to START and check White wire on key switch for voltage.
If no voltage on White wire with key at start, replace key switch.
If yes, has voltage, go to clutch/brake switch and check the 2 White wires for voltage when key switch is turned to start. With brake pedal up, only one white wire will show voltage, this is normal. With brake pedal down, both white wires should show voltage. If neither White wire shows voltage, check wiring between brake switch and key switch. If only one White wire shows voltage when pedal is down, replace brake switch. If both White wires show voltage with pedal down, move on to the PTO switch to test it.
On the PTO switch (with PTO switch off, brake pedal down, and key switch at START)check White wire at terminal C for voltage. If no voltage, check wiring between brake switch and PTO switch. If yes, has voltage, check for voltage at terminal G. If no voltage on G, replace the PTO switch. If yes, has voltage, move on to the starter solenoid to test there.
At the starter solenoid, (PTO switch off, brake pedal down, key switch at START) check for voltage at the small white wire. If yes, has voltage, check the small black wire (on the second small post) for voltage. If you can actually read voltage on the small black wire at this time...........that means that the ENTIRE starting control circuits are good, BUT....this last ground circuit is OPEN. If you check for voltage on the small black wire at this time and DO NOT see voltage, the ground circuit is good. This would indicate that the solenoid is indeed bad in respect to the operating coil of the solenoid.
If the small black wire shows voltage in the test, you need to repair or replace that ground wire.
Do these tests and we can address the charging circuits later, right now we need to get the starting circuits in good order.

Thank you Mownie, for being patient and sticking through. I followed your post step by step. All was well until I got to the PTO part. I stuck the probe in at teminal C hard enough so it would stay put while I touched the other to ground and had a free hand to turn the igintion to start. At that time, the solenoid clicked loud and clear! It seems to have been a loose wire at T-C.
I'm elated! Thank you again!!
Thank you to the other posters also.

OK, glad we got that nailed down.
Now you will just have to try using the machine to see if your electrical system will run the PTO AND recharge the battery enough to allow something akin to "normal".
Signs to watch for that the charging rate is not adequate will be either, or both, of the following.
1...The PTO suddenly quits working while you are mowing (blades stop).
2...The engine will not crank again (weak battery) after you shut it off following a mowing session.

I suggest you DO NOT USE your lights at all, perhaps just remove the bulbs from their sockets altogether.