Spidey 1984, it sounds like the guys that are working on your motor, aren't familiar with your model and age motor!!! A lot of the shops today, don't know how to work on motors older that 20 to 25years old. They have not been trained on them and they don't put much interest in them because they are not money makers for them. Most of the time the cost of the labor is worth more than the engine.
But, let me tell you, that engine you have there is one of the finest motors put out by Evinrude (OMC). The 18hp motors are pretty bullet proof if they are not severely neglected!! They are relatively easily to work on if you have some mechanical abilities and are willing to be patient.
The ignition system on that motor is very common to OMC and is very simple to diagnosis and repair. Pappy is right, it could be as simple as a short in the kill switch which connects to the points and condensers.
Here print this up and give it the "Mechanics" working on your motor!!! I would check into what they are charging you and put a stop to the on going hourly charge because they are going to take you to cleaners and they don't have a good grasp on the situation. They should have been honest up front concerning there ability to work on an older motor that they are not familiar with. At least charge a flat rate fee for their learning curve!!!
Have them test the continuity of the all the wires especially the kill switch wires going the points. Unplug both sets of kill wires from the points and condensers. If spark returns then the kill switch is bad.
Here is some information that will help you evaluate your ignition system with the flywheel popped off.
If you don't have a harmonic balance flywheel puller, you can make a flywheel knocker tool. One of our many distinguished member put this tutorial together on how use and make a flywheel knocker to safely remove a flywheel. I have tried and it workings well. I have both the flywheel knocker and harmonic balance flywheel remover.
Anyway here is the Flywheel knocker tool link.
https://www.aomci.org/cgi-bin/yabb2/YaBB.pl?num=1309393684
Your going to need to inspect your point, condenser and coils. They are located under the flywheel. Hopefully all you need to do is clean and regap your points and you might be in business. Still check your coils and condensers and plug wires.
Here are two link to show you how to test your coils and condensers.
https://www.youtube.com/watch?v=KT8rk5QWgS0
https://www.youtube.com/watch?v=l6eSXYmENDY
How to replace your coils, points and condenser. Please take digital pictures as you go, so it will help you return everything back in the right order. Keep cheap zip lock bags available to put your parts in so you don't lose them. They are small.
Here is a diagram of a generic OMC (Johnson/Evinrudle/Gale) ignition assembly. You will have to remove the coil designated for the top cylinder and put the oil wicker in. It should be already be coated with a very light oil. (not grease). The purpose of the oil wicker is to lightly lubricate the outside riding surface of the cam so the point shoes do not prematurely wear. If you look at the points they have little shoes that ride along the cam. Please make sure the (breaker)points cam is on the correct side or the ignition will be out of timing. It should have the word [highlight]top[/highlight] machine written on the side facing up.
FYI: You can only set(gap) one set of points at a time. Put the flywheel nut back on(turn with a wrench or ratchet clockwise) to allow you turn the crankshaft.
(Please remove both spark plugs to make it easier to turn the crankshaft and prevent accidental starting)
You gap the point to 0.020 when the point shoes is at the top(high point of the cam). It should have a mark along with the word top. Then you will turn clockwise to the next set of point 180 degrees and set those points the same way. You will notice that the point of the previous set will be closed and when you come around again they will open up. *** When they are open no current is allow through. This is how you set your timing with the points.***
When you go to set the point's gap. Very gently snug the anchor screw, then adjust the gap with adjusting screw and the feeler gauge until the feeler gauge is sliding through with slight resistance only. Then tighten the anchor screw. Repeat procedure with second set of points. Please make sure your hands are clean and the feeler gauge is clean, because oil on the points can foul them up and create resistance....poor or no no spark. ALways use a spark check to evaluate spark. It should jump minimum 1/4 inch. Blue sharp snappy spark.
Here is a picture of a spark check...Cheap $6
Here is a picture of how to tell which wire is going to the correct cylinder. Thanks to Garry for providing the picture on other post.
If your using the existing wires then cut about 1/4 inch of end going the coil, so you have clean un-oxidized copper contacting the spiking in the coil. Twist the end of the spark plug wire onto the coil spike. If you have replaced the wires, make sure they are 7mm copper metal core and not the automobile stuff.
***** Please make sure two things*****
1.) Make sure all the wires are tucked away under the flywheel and not rubbing up against the cam or crank, because with will eventually get damage and create a short, then no spark!!
2.) Make sure the coil heels (ends) are evenly lined up with the mounting boss.
Here are some pictures. (Compliments of JBJennings..nice fella)
Lining up the coil heel with the mounting boss prevent damage of the coils and the flywheel magnet, prevent rubbing as the flywheel turns.
[highlight]*** Make sure the throttle is advanced to that start position***[/highlight]
Here is another picture that Garry (thanks Garry!!) supplied on another post with some modification.
Both diagrams, should answer your questions.
*****
Here is a diagram of your ignition plate. Look at items 36, those are the wires that connect to your points and condensers to prevent spark when you are trying to kill the engine. Parts 38 are the connections hanging below the ignition plate on left hand side facing the front of motors. They connect to the wires that lead to kill switch on the face plate in the front of the motor. If that kill switch is bad, it will short the circuit and prevent spark. So, if the "mechanics or you disconnect the wires from the kill switch at part 38, then spark should return if the kill switch is bad. Part 27 in the second diagram is the kill switch. You see it has connector end that clip together with the wires #36 in the first diagram at the end part #38
Good luck!!