I have an 03 VMAX 200, it seems to start right up but after running it for alittle while it gets harder to start. I thought it may have been from some cheap oil I had to use in a pinch but thats gone now and im back to my premium blend and also added some ring free additive. Ive been to the lake the past 2 afternoons to try and get the good oil and additive cyclying through the system, also changed the plugs. Any suggestions?