Johnson/Evinrude Marine engines - 1972 johnson model 65ESL72S was running fine and then quit.

I have a 72 johnson model 65ESL72S. I was running the boat and the motor quit. I found the wire..

I have a 72 johnson model 65ESL72S. I was running the boat and the motor quit. I found the wire that plugs onto the neutral swith or button was off. I put it back on and it wouldn't crank. I was told the powerpack had went out, so I put a new one on the motor. It still wouldn't crank. I took it to a mechanic and he said the stator ring was bad and replaced it. It ran fine at his house, but when I took it to the lake and tried to run the motor, it wouldn't plane the boat and died and want start again. What should I check now?
New power pack and stator ring

First thing is to always check your compression. Once that is out of the way you will need to check spark. A spark tester is the best way to ensure a good spark. You can buy an inexpensive single spark tester at any auto supply store for just a few dollars.
Put the spark tester on cylinder #1 crank engine and look for a strong blue spark. Do the same with cylinders 2 & 3.
If you have good spark now check the timing. Easiest way on your engine is using a remote starter switch. Put on lead on the positive terminal on the starter solenoid and the other lead on the small yellow lead from the key. The other terminal goes to ground.
Crank the engine in gear with the key on, fuel disconnected, and check the timing with a timing light. Check the full throttle timing. The starter switch will allow full throttle. Keep anyone away from the prop.
Once the timing is set or OK, without cranking the engine move the throttle from idle to full throttle, observe the linkage on the side of the engine that the carb linkage is opening all the way.
If the carb is opening, spark is OK on all 3 cylinders and timing set and the engine is not getting to speed, you will need to check the fuel system.
If the engine has been sitting a length of time the carbs could be gummed up.
Remove the air silencer in front of the carbs, remove the slotted plugs in the bottom front of the carbs, drain the fuel into a paper towel. If there is water drain the fuel system. If the end of the plug has a brown or blackish gummy substance the carbs will need rebuilding.
Finally I would recommend using a good service shop not someone in their backyard.

Jeff,
The motor was running fine, before the neutral switch wire came off.
The compression is 135 on all 3 cyclinders. The carbs have been cleaned and rebuilt. It has new plugs.
After the stator ring was put on the engine it ran, but now it has no spark to the plugs.

On the power pack look for a black/yellow wire. Unscrew the screw and remove the wire from the power pack.
If you now have spark then you either have a short on the wire or the key switch is bad. The black/yellow wire kills the ignition by putting a ground on the ignition.
The neutral start switch only prevents the engine from starting in gear, it does not affect the ignition system.

The yellow and black wire made no difference when I took it loose I still had no fire. Do you think it could be the timer base?
Everything on dealing with the ignition is new now except the coils, timer base and wiring harness inside the motor crowl. Is it possible to have another wire causing a ground mnot letting the motor fire?

The way the ignition system works is the stator has a charge coil, and alternator coils. The charge coil sends an electrical charge to the power pack which stores the charge. The trigger has 3 coils which send a small electrical charge to the power pack when the flywheel passes the coil which is indexed to the crank. This controls the timing. When this small charge reaches the power pack it in turn causes the power pack to release it's charge to the ignition coils.
The black/yellow wire grounds the power pack to stop the ignition from firing.
The charge coil on the stator can cause loss of fire on all the cylinders.
Failure of the power pack can cause the loss of 1,2, or all 3 cylinders.
The trigger has 3 coils so it is doubtful that you would have a failure of all the cylinders.
The ignition coils only affect that cylinder.
The only way to definitively check the power pack or stator charge coil is using a peak reading voltmeter DVA. However you can check the stator coils with an ohmmeter. Just check for a short to ground. Or an open between the two wires. Same with the trigger coils. Don't worry about the yellow alternator wires.
So long and short of it is probably your stator or power pack is bad.
If you have access to a DVA you need approximately 180 volts from the charge coil and the power pack to the ignition coils.