I just purchased a used Key West 1720 DC with a 90 HP Force. Can someone help me figure out what year this motor is? The serial number is QE122348. The only other number I can see on the motor is near the top spark plug - 900-819857-02 - looks like a part #? Everyone tells me the motor is junk, but it runs great and I would like to find out the year so I can properly maintain it. Thanks for your help!