Expert: Everett Peacock - 12/15/2009

Question
my old 650 starts and runs fine until it has been working for a few minutes.after a while it will pick up a vibration and lose power as if there might be a seal that is leaking. if i back out of the throttle and get back into it the problem goes away temporarily.and once warm likes to stall at idle .

Answer
sounds to me like it may be getting water in the cylinders...there is an exhaust plate on the side of the powerhead, it has water on one side and exhaust on the other. Over time they corrode a hole in the plate, letting water get in the engine and over time will scoor the piston and cytlinder..