Yamaha 2 Stroke

I have a Yamaha 2 stroke and am having a few problems. When it runs right, it runs great. The problem is that after about an hour it drops from 3500 RPMs to about 1000. It dosnt fix itself the next start up either, it stays at 1000 RPMs for a day or two. I have noticed though that after a wavy day it tends to work well again right after that. Other symptoms are that in neutral after running for a while it will have this screeching sound as if a bird was chirping inside. Something interesting that happened was that when i was winterizing the boat last summer, i pulled the fuel line out of the engine while it was running and the left over fuel already in the engine started to run out, the engine ran much smoother. could this mean that i am getting too much fuel inside the engine after running it?

thanks

If it works well after hitting waves then sounds like something is loose and when you hit the wave,the impact makes it get connection again.check all wiring connections,might be that simple.start with the simple things and work your way to bigger and more complicated things.

What is the model number?

thats one of the issues, i dont have the model number. ya and ciscokid i heard that it could do with a sensor that is triggering for some reason. could it be too much gas entering the engine? it dosnt shut down completely either, it drops about 2000 RPMs. but still runs. and one time i can to shore after it dropped RPMs and then turned around and jumped off again with fun speed so maybe it is something coming loose or sticking?
also i keep reading online about this and people with similar symptoms say that they think it has something to do with the fuel pump

Better find a model or you are dead in the water if you want to buy a part or get a diagnosis that is even close to meaningful.