1996 75HP mercury out board top cylinder not firing

[Reter2023]

I have a 19 9675 hp mercury outboard, the top cylinder is not firing. I have had compression checked by three separate people compression is good on all three cylinders, I have replaced the coils, the spark plug caps, the CDI box the voltage regulator and the stater reads good. I have stuck float needle in the spring when I first brought the boat out. I had the top carb cleaned and put back together and readjusted but every time underload the boat will not get above a certain RPM my guess would be 3000 4000 RPM. My speed is at 8 mph And the idols just fine but has a little hiccup probably every 20 seconds. When removing the top spark plug cap, the motor does not run any different. But when taking off the spark plug caps for cylinders two and three, the motor runs like it’s misfiring like it has a problem, which is how it should be acting. Is there something I’m missing here that could be super simple that will underload my motor is just not getting up to speed or something simple in electrical or something with the spark plugs. I need help.

 

[fitz73222]

Leaking top crankshaft seal, not enough fuel charge to fire.

 

[Reter2023]

I don’t have any other leaks of oil anywhere though

 

[Reter2023]

The shop had working on it said he has adjust it a lot since it kept fouling plugs, and he finally got it where it “needed” to be