i have a 2004 Honda Rincon 650 (carbureted) last ride started acting funny. Would rev up and down on idle in neutral and shake the four wheeler like it was going to stall. Started working on it yesterday and is running extremely rich and black smokes when throttle is pushed. I have adjusted the A/F screw on the carb and seemed to not do much. I noticed the choke cable is broken so i have one on order as we speak also a new air filter, fuel strainer filter and will clean the tank as well. what other reasons could cause this to happen? ALSO stalls when the exhaust is under water while at idle. The only way for it not to stall is to keep thumb on throttle. So this being said i have sucked up some water in the exhaust a few times recently but the air box and the oil are fine i would just turn the four wheeler up and dump the water out of the exhaust and it would start back up. Not sure if this could be a problem?