Low vacuum in right carb and wet plug

When I put my hand over the right carb inlet there is very little vacuum pressure pulling my hand toward the carb, and I noticed that plug looks wet/glossy.

On the left hand side, the plug looks normal and the vacuum pressure pulls my hand straight against the inlet.

Is this a carb problem? compression problem? valve problem? something else entirely?

thanks,
Chris

Start with a compression test, wet plug means it is not burning the fuel entering the cylinder. Compression, fuel spark, these are all needed.
Have you a gauge for this? Have you done a valve adjustment?
Also check you spark, coil, etc.
If the compression, spark, are oK. Then its pull the carbs and go through them, you may have a high fuel level do to a bad float, or the needle and seat for the fuel level.

Whens the last time you had a good manometer syncronization/testing done?
It is required maintenence.