I have a 1997 Ultra 680 Polaris which I purchased recently. I have very oily spark plugs and oil coming out the exhaust. The engine won't idle, it has to be feathered. I took the carbs apart and they look very clean. It's not very responsive on the throttle compared to my brother's Ultra which doesn't have rich problem. I looked over the oil pump, and I do not see an adjustment. Does anybody have any advice on how to fix this problem?