i've been having a problem with the engine now wanting to die when you turn the key off. it seems as though it sputtering still trying to run when you turn the key off. it did this almost everytime when i took it out the first time, but since they i replaced the spark plugs and it did it only once after wards. my question is why would it be doing this? the motor starts up and runs really well, but could it still be a timing issue? the motor is a 3.0l mercruiser. any info is appreciated. thanks.