Bought this boat last fall. While working on other problems I bumped the distributor and it moved. The bolt was not tight. I am familiar with timing engines from 20 years ago, so after reading the Seloc manual it seemed like a snap. When I looked for timing marks on the front of the motor,all I could see was a tab on the top left with a v notch in it. Looking at the harmonic balancer, there are two grooves in it a few inches apart. I don't see any TDC marks or advance or retard degree marks. The engine serial # is OM060235. Where do I start? Thanks, Cliff