I have a 98 ts770 that makes an initial cold start flawlessly. However, when idling, the motor seems to load up. After you take off though the motor cleans right back out and runs great. And if you shut it off for more than a minute or two it will not restart. Seems like it is getting too much fuel. I have installed an oil pump block off and I premix 50:1. The carbs seem to be fine. I'm just trying to figure out where to move next. Any help would be appreciated.