2004 yamaha 4 stroke outboard

[Jason2tpa]

I'm now convinced this OP is pranking us. This isn't the only yamaha forum the OP has posted multiple threads on the same topic, as well as continuing to NOT follow the simple advice given.

[pstephens46]

How many got a PM from him too?

How does he determine #4 is missing?

[beantown]

Maybe he went to go look for #4 carb, since it's missing.

[99yam40]

motor needs good compression, good spark, spark at the proper time, and the proper fuel to air ratio.

If you are absolutely sure you have proper compression and spark and the timing of proper spark is correct on all cylinders, then make sure you are not getting water in the cylinder.
what did the spark plugs look like?

you will need to find out what is wrong with the fuel to air ratio if everything else is good
is there too much fuel, too little fuel?

where could extra air come from on #4?
where could too much fuel come from?
not much can change the amount of air let in except cam and valves not doing what they should be doing.
running too lean could be air coming in from somewhere behind the carb or the carb not metering the fuel properly.
have you checked the size of jets in carbs and checked for something plugging jets?