A 96 could have lots of miles, you didn't say and I don't know the environment where you operate, such as desert or swamp. I know you have been in the carb a bunch but a couple of thing to look at and you don't need to pull the carb to check. Does the carb slide lift all the way, and is the needle, some people call it the metering rod secured, meaning it can't be pushed up in the slide. While we are on the carb, there is/was a rubber flap at the back of the fuel tank that I have seen plug the intake, the intake tube should stick up through it. You may also have a plugged exhaust, the end pipe comes out and you can check it, they can be a bitch sometimes if they are really stuck. Don't buy clutch parts yet, if it is clutch, and it doesn't sound like it, it will probably be the shoe clutch, it drives off of the crank. Also what does the spark plug look like, is it sooty or white or wet. Is there any popping or sputtering, or just the rpm fluctuating?