Replacement motor not starting .. wiring help? ?

Hey guys.. newbie from australia here..

I have a greenfield fastcut34.. was powered by a briggs and stratton 19.5hp Intek.. I've purchased a b&s 19hp pro series motor to replace it.. got a new solenoid as well..

Have fitted the motor and replaced the solenoid.. have wired to the starter and block for ground.. now the engine will spin no worries when I turn the key but it doesnt fire up..

The wiring was a bit different.. I'll attach some pics in the hope of some guidance to wire what needs to be wired..

Behind the ignition there are 5 spade connectors marked B G L M and S.. the new motor has a 6 port plug attached with 4 wires going into it.. (and of course it's not plug and play haha)



I've removed the wiring for the lights and clock as someone had butchered them a bit and I have no need for them..

Firstly your crimping really need to be improved.
Those terminals will corrode in no time flat and cause a lot more headaches .
Terminals are :-
B = battery, 12 V supply
G= Ground usually done with short strap to a bolt under the dash
M= Magneto ; connects to G to turn the engine off & connects to nothing to make the engine go.
S= Start ; B connects to it to send power to the starter solenoid via the safety switches.
L = lights
A = alternator; Connects to B to supply power from the alternator when the engine is running and backflow to recharge the battery.

On your plug the grey wire should go +12V when the ignition is on to energise the solenoid under the carb , connects to the L or A on switch
the Black wire should go to the magneto and be open circuit switch on & ground switch off.

Because you have done single wire hook ups there is a chance you have sent 12V down the magneto wire and if you have then the chip in the coils will be fried.
So start by removing the engine cover and pulling the kill wires off the coils.
Crank the engine, if it starts they are OK if it is a twin, do each side one at a time just to be sure.

The 2 red wires should be the AC feed from the alternator which will of course need to be rectified.
If one is red & one is orange then red is for recharging & the orange will be for lights.
We really need a pickie of the old engine plug & mower plug.
Usually AC rectification is done on the engine side of the plug so something appears to be missing.


Alternators are common across most of the range, so you should be able to take the old alternator off the old engine & swap it to the new one.
Briggs supplied the exact same engine with a lot of different alternators depending upon the end use of the engine.

Is your fast cut the deluxe one with electric blade switch or the manual lever blade engagement because the electric clutch needs a bigger alternator.

Do yourself a big big favour & get an uninsulated crimping tool from J-car plus a pack of female spades & insulating sleeves and some heat shrink big enough to slip over the wire end of the sleeve.
pop the heat shrink , about 1" long on the wires then sleeve, crimp the terminal slide the sleeve over & finish off with the heat shrink over the top.