Mercury 50, 3-cylinder, Won't Start

I have a 50 hp 3-cylinder that will not start. Not surer of the year. Serial OA987473. Working on it for a friend. It has not run in at least 2 years. It is very clean and is in good cosmetic condition. The steering cable is frozen, so I am not too sure about the two years thing....
Compression is 120 across all three.
I have diagnosed and swapped out a bad switch box that was stopping spark.
I now have compression and spark.
I have run through fuel delivery; fuel pump squirts when engine cranked.
I went through each carburetor, albeit not a rebuild; same parts; I put wires and air through jets, etc...
Carburetors get fuel to the bowls. I can get fuel pouring from the carburetor drains.
I squirted premix into the carburetors and got one and only one, back-fire pop.
Still no start.
What is this sick puppy trying to tell me?
Thanks,
J

Re: Mercury 50, 3-cylinder, Won't Start

Maybe double check your switch box wires?
A couple crossed wires, which is very easy to
on older motors when the wires are faded,
will mess up your firing order

Mike

Re: Mercury 50, 3-cylinder, Won't Start

Right. I will.
Let me ask this: going to the coil from the switch box, is it green and red to coil #1?
Also, I notice the propeller has a good chunk taken out of it. Could a violent hit at the prop shaft change or shift the timing?
J

Re: Mercury 50, 3-cylinder, Won't Start

That does sound right, green\red #1 green\white#2 green #3
and a hard hit shouldn't change the timing, but
It the center magnet on the flywheel came loose
the timing will be off
You can check the timing with a light while cranking

Re: Mercury 50, 3-cylinder, Won't Start

Checked engine harness and we are correct and we re wrong at the same time, as follows:
From the switch box to coil positive:
Green/red to top coil which fires cylinder #3.
Green/white to middle coil which fires cylinder #2.
Green to bottom coil which fires cylinder #1.
I don't see how coil inputs could get crossed. The leads are not long enough.
I'm gonna have to get on it with a light.
Does this flywheel have a key? On this model, how is the flywheel indexed to the drive shaft? I see a splined shaft in parts lists. Yuck.....
Thanks,
J