Yamaha 40 wont run on all 3 cylinders

[w2much]

I have rebuilt the carbs, spark is blue hot and jumps a mile, compression is even at 110 per cylinder. The motor runs and idles fine on the top two cylinders. The bottom cylinder even though it has good spark and compression, the plugs are wet, will not ignite. I have beat my head on this. Today I realized that the ignition switch which is meant to activate the fuel primer does not come out. It is stuck on the pushed in position. My question is might this be the probable cause of number 3 (the bottom) cylinder from igniting.? If the switch is stuck in does that mean that the primer is continuously pumping fuel into the lower cylinder thus flooding it to a point where it will not fire? When pressing the primer in I do not hear it activate in the engine.
How do I test the primer on this engine, it has a blue and a black wire going into it?

 

[w2much]

Forgot to mention late 80's 2 stroke carb.

 

[99yam40]

Posting the complete Mode # helps others know what motor you have.

have you check the fuel pump?
it gets pulses from the crankcase on #3 to drive it, and if it leaks into the crankcase it will cause over rich condition on #3

 

[River Explorer]

I saw something on this just the other day on a 90hp 2stroke. Fuel pump was making the lower cyl flood. sounds like the exact same symptoms.

 

[River Explorer]

The 90hp was a Yamaha 3cyl and I believe it functions the same