i have a 80hp yamaha efi 4 stroke 2005. was out yesterday engine was running fine then all of a sudden it started to lose power and surge then just died. turned key for a few seconds and it started up and ran again for a few minutes and doone the same thing . this happend everytime . i checked the batterys and the negative power cable was broke so i fixed it and the engine started again but after a few minutes done the same thing again. got home and conected water to the engine but this time it was very hard to start , after a few minutes i got it started it ran away for 10 minutes of so before i stoped again , now i cant get it to start at all it will turn over but it dont seem to be fireing. iv checked for fuel and all seems ok and is fresh fuel. checked fuses there fine. what could it be could it be after blowing the cdi if so how can i check. any help please. thanks