I have a problem with throttle on my WaveVenture. It's not the throttle cable, because I can disconnect it from the carbs and it moves freely. When I attempt to move the throttle linkage on the carbs it is very tough. I started noticing the problem when I would release the throttle and the rpm's would slowly come down. As a matter of fact it won't come back down to idle unless I manually move the linkage. I have attempted to clean all the pivoting parts on each carb, but no real luck. It did make it a tad better, but not enough for me to feel safe. Any ideas before I take it to a tech and let them work on it. All help and suggestions are greatly appreciated.