Brand new B&S 17.5 swap in

My old 11 HP B&S wouldn't start and had only 67 PSI compression so I bought a new 17.5 from Northern Tool.
It was the cheapest one of equal or greater HP, cost about $500.
I don't have much of a workbench to learn how to rebuild a splash oil governed engine.
Turns out I couldn't get the drive pulley off anyway.
It's a recoil start, looks like my old starter will fit, and it has a solenoid on the carb bowl.
It bolted in the same holes nicely but one of the hinge pin brackets had to go.
Lucky the hinge pins weren't being used.
The solenoid has a black ground wire and a gray wire that I expect will need 12 volts to run the engine.
The other side has an alternator & rectifier.  A yellow wire goes from the engine to the rectifier, then a red wire is the output, I think.
A 2-wire connector has the gray wire and another black wire that I think is the engine stop wire.
Am I right?

Yeah I would bet that black is the kill.

I think maybe a headlight or relay plug & socket could substitute for those OEM connectors, or maybe just pick a pair off the display hooks. Unless they have the B&S connectors on the shelf at John Deere.

Spade terminals will work fine

Yes, I failed to think inside the box.
I have wire, connectors, shrink tube, and 2 bus blocks illustrated elsewhere on this forum. I took some time to add a dashboard for an hour meter that I want to be accurate, so the first start is delayed.

I bought a new starter for my old engine.
Later I found my old starter could be made to work so I put it back in.
The new starter came with 2 pinion gears.
One seems to have a wider root, otherwise they look the same.
I attached some pics with bits of tape measure copied and pasted at the same scale.
I plan to match one to the flywheel on the new motor when I get around to it.
Any advice about which is correct?
Maybe keep the old starter until it's really broken?
The old engine is an 11 HP circa 1988.

When it comes to the gears, count the teeth. One gear looks to have more teeth then the other. Count the teeth on the old gear to match them up. If they all have the same number of teeth, the it cones down to which way the gear spins. This is determined by the bevel on the edge of the gears. The bevel side of the gear goes behind the direction of rotation.

I meant to post about that sooner. I put the new starter in using the screws from the old engine. My battery is weak but the starter cranks well with the gear that came on it.
The pictures and/or my brain have tricks in them.
Just before the install the gears looked alike except the one not on the starter has the bevel on one side and the roots looked the same.
Anyway putting the starter on was easy.
One glitch was resistance to turning the longer screw into the blind hole.
It worried me so I tried one of the short screws that held a thin plate where the starter goes. It didn't go deep enough and stripped some thread. After double checking the hole depth I muscled the old starter screw until it was tight and not stripped.

The pull start mechanism sits on top of the shroud with 4 screws in a square pattern so I think I can rotate it to make a pull from the driver's seat possible.
The pic with the starter also shows how the stock muffler interferes where the front hinge bracket would normally be.

Yah, be careful with pulling the starter string from sitting in the seat, it is possible to give yourself a right hook to the chin, LOL.

I'm going to move the hitch too, maybe put a small receiver on it.
I don't want the trailer tongue to ding up the valve cover.

1st start today

Used the pull start because the weak battery wouldn't kick in the starter.

A couple of pulls didn't work, then I tried stepping on the clutch/brake and it started.
That may be voodoo because if it wouldn't pull-start because of the clutch not being pressed then it shouldn't have kept running without the clutch being pressed, right?

It didn't charge, at idle or full throttle.
It was getting dark and I didn't check if the engine hour meter was running as it should.
I wired it to the rectifier output to make it record actual run time.
We'll see if that logic works out.

At idle it had 87 or 88 db at the steering wheel and 91 to 96 db within a few inches of the stock muffler.  At full throttle, no load it had 99.1 to 99.7 db at the steering wheel.
Less than 8 hours of exposure to 85 decibels is considered safe by OSHA so this is ear-plug territory, I think.

There's still a ways to go on the engine cover and I haven't put all the belt guides back.
On that subject I have my fingers crossed that I put back all necessary for the drive belt and the mower guides will be obvious enough.  So far, it's not so obvious where they go.

For a fuel supply I bought a plastic 3 gallon outboard motor portable tank.
It didn't come with fittings.  I bought an OMC hose & fittings because I am familiar with the design.
I cut the engine end (farthest from the squeeze bulb) and clamped it to the filter's inlet.  It was loose on the nipple so I put a short piece of shrink tube on it so there was more friction slipping it on, then clamped it with a hose clamp.  I need to build a shelf behind the seat to hold the tank or make a smaller tank.  Putting it above the engine seems risky even if our generator's gas tank is above the engine.

The engine running with the key switch on and shutting down when the key switch is off means the wiring in general is ok and consistent with the opinions expressed earlier in this thread.

I suppose this ends the swap-in.  The build and fixing the other stuff likely belongs in separate discussion
s.

Would have been kinda cool to have put an hour meter on my simplicity when I built it, just for the heck of it but oh well. Glad you got it all hooked up for the most part anyways.

After last winter the solenoid or other stuff didn't work well enough to make the starter work.
I put in a 30 amp key switch and tossed out the relay circuits. The various safeties are bypassed but I put in a jet ski type of kill switch. It is a normally closed switch that opens when the safety cable fork is stuck on it. That makes it work as a kill switch for the magneto circuit.
Everything worked for a while, then the starter stopped engaging.
I had a day planned and the pull start was good enough.
After some time idling up & down a hill in low gear it wouldn't start.
An investigation is pending as time & dry weather permit, I suspect it got some bad gas. I have an inline fuel filter so it shouldn't be debris in the gas.

Hope it is bad gas.  Easy fix.  Seems to be a lot of that going around down here lately.

Cold start, full choke, didn't hook up the fuel tank. It started after a few pulls & ran until I turned the key off.
Maybe it somehow got flooded that day.
I had half a mind to leave it running while we clamped on the trailer but it was facing up hill a bit.
At my job when stuff works like this we call it FM or Freaking Magic.
I'll do other things today and hope it doesn't happen again