Home › Forum › Ask A Member › How Important is OMC Ignition Timing? › Re: How Important is OMC Ignition Timing?
OK, this covers how to determine when the points open. If you don’t have a timing tool, you can still get this done… I use some kind of stationary pointer that can be screwed on to the block, and get close to the flywheel.
First, make sure the mag plate is locked down and won’t move. Adjust the first set of points using a feeler gauge, then get the flywheel to where that set of points is just opening. Put a mark on the flywheel where the pointer is. Then use a tape measure to determine the circumference of the flywheel. At one half the circumference from the first mark, put a second mark. (This is 180 degrees from the first mark.) Line the second mark up with the pointer, then adjust the second set of points to where they just open.
I was quite surprised how far off the initial settings (just using gap) were on a Scott 10 hp Pennant I had a while back. It was probably 15 or 20 degrees off. The motor ran better, and idled a LOT better with the timing adjusted correctly.
Tom