View Full Version : Need help with B/S engine swap FAST -PLEASE !

07-17-2007, 04:17 AM
Hey guys, have a 2006 Toro timecutter z420 with a Briggs 16 hp Intek AVS that just took a dump on me,governor went crazy and revved the engine until the thing broke a rod.Ordered a new Briggs 18 intek as a replacement,coming tommorow.Only thing is the alternator is apparently different on the new engine , from my original one.The guy told me i would have to use my old "alternator and regulator" off my 16 hp, onto the new 18 hp model.Question is, how do i get the flywheel off the top of the engine ? And does it slide on into a keyway onto the shaft ? Basically wondering if there is only one way this thing comes on and off, or do i have to mark the teeth on the wheel ,with somewhere on the block,so the timing doesn't get thrown off ? Currently there is only 1 wire coming from my 16 hp motor, and apparently the new 18 hp is a "dual alternator" ?...do i have to take apart both motors and swap alternators,or is there and easier way to do this ? Thanks alot if anyone can answer this,never removed a flyweel or alternator before, a quick explanation would be great, i'm in a big bind here.Here are the model #'s from the engines

1. 16 hp junk motor = model # 286H77 TYPE 0165 E1

2. 18 hp new motor i'm putting in = model # 31P777-0602

Bill Kapaun
07-17-2007, 05:37 AM
The flywheel is keyed to the shaft, so it only goes on one way.
The recommended removal method is with a flywheel puller, but others have used the hammer method with "some" success. I'm not sure if you want to risk it.

According to the IPL, your "old" motor is equipped with the "tri circuit" alternator. Should be a BLACK wire going to a GREEN connector. The connector is your diode that converts your AC from the alternator to 9 AMPS DC
The new motor has a "dual circuit" system. It puts out 14V AC on the RED wire and 2-4 AMPS DC on the BLACK wire. It goes to a WHITE connector.
(Connector colors are important in Briggsville)
IF you have an electric PTO, you'll have to swap the Flywheel AND Stator from the old motor. The new one only has enough capacity to slowly charge the battery and maybe run a small headlight off the AC part.

Bill Kapaun
07-17-2007, 05:42 AM
PS you can down load IPL's at the link-

07-17-2007, 02:04 PM
Ok, so i definitely need to swap out BOTH flywheels and alternators - i'm assuming they are both a universal fit then on many of brigg's motors.One more question, is the bolt on the top of the flywheel a regular thread style ,or is reverse thread ? I can't seem to get that bolt off no matter how hard i turn, is there a special tool for preventing the flywheel from turning the motor,as you try to loosen the bolt ? Thank you much for your help

Bill Kapaun
07-17-2007, 03:30 PM
"Ok, so i definitely need to swap out BOTH flywheels and alternators"
Yes. To make sure everything works right.
According to the IPLs, at least one of the flywheels is used on both engines, but in a different charging setup. Possibly the same flywheel would still work on the same engine, but it's not worth taking a chance. the magnets maybe stronger/weaker and possibly cause problems??
The STATORS MUST be changed. They are different!
If you don't have an impact wrench, you can try the piece of rope in the spark plug hole trick.

07-18-2007, 02:16 AM
Thanks Bill, ended up using an impact wrench borrowed from a friend to remove the top bolt - what a breeze with correct tools.I got the motor swap done and installed, now i just got to mount the alternator and other flywheel tomorrow....once again, Thanks for the fast replies

Bill Kapaun
07-18-2007, 02:23 AM
Glad everything seems to be going OK.
Keep us updated!
I think you'll find swapping the stator is actually the preferable plan. Otherwise you'd be messing around trying to get the right connectors etc.
this should be more "sanitary".
Did you notice any difference in the flywheels?

07-20-2007, 04:49 AM
i swapped the stator, flywheel,and coil from my used motor , onto my new one...fit right on no problem,just had to cut and reconnect some wires from the different plugs.All said and done, it works well so far.Brand new 18HP Intek from smallenginewharehouse.com for $449 plus freight, not bad at all - considering all the local dealers around me ALL wanted about $1200 plus tax, and freight just to replace my original less powerfull 16 hp motor.BTW, i did end up having to pummel the flywheel upward with a hammer and bar to get it off, not the best way to do it, but i didn't have a gear puller.Now i'm going to try and have Briggs warranty out my old motor , hopefully with a new one, or at least a short block., as the governor is what caused it to over rev to begin with it appears...Appreciate the quick replies :drinkup:

Bill Kapaun
07-20-2007, 06:09 AM
"just had to cut and reconnect some wires from the different plugs"

I expected everything would hook up the same??
Which plugs did you have to modify?
Curious minds.....
Glad it's working!

07-20-2007, 01:52 PM
the wire coming from the fuel solenoid and coil were all tied into one harness on the new engine,that included the stator wires, different plug.Just cut them and tied them back onto the old motors plug in connector,and reconnected the alternator wire back into it's own original diode plug in, green i think.