I have a Johnson 90 2001 model. It has the optical ignition system. In the manual there is a special OMC tool for timing that you plug into the electrical system. It costs $300. <br /> Can you time this engine any other way? How? If you know could you send me any and all info on how to do this. <br /> I rebuilt this engine from ground up. It had a hole in the top of no.1 piston. Some say from detonation or bad fuel. I want to make sure it was not a timing problem. Thanks for any help. 