Thanks, The only external deference I can tell is the 87 has a ground that is white and the 89 has a black with white stripe on it.The center and the external check the same. checked with a set of calipers.The plugs are identical.When I first start the engine #1,3,5 cylinders do not fire for about 10 sec. then all cylinders fire great.Took it and put it in the water and seem to do great.What you think?
Cylinders 1,3,5 momentarily have their spark/ignition interrupted when shifting... a feature incorporated to allow the engine to shift "out" of gear. This feature activates so quickly and for such a limited amount of time that one doesn't normally notice it.
Some rig and engine combinations, "Not All" are impossible to get out of gear without this feature... in which case (my opinion), the feature is not needed in all cases. It depends on the propeller also... I encountered a large Mako in 1988 with new twin 225hp engines using "Raker" propellers. Impossible to get out of gear at an idle when launched, but perfectly normal on a flushette... Had to change propellers.
Since all three (3) cylinders are affected momentarily when starting, it's possible that the shift switch is sticking for some reason. Follow the Black/Yellow & Black wires on the starboard side of the engine forward and down into the shift linkage to find the switch, then disconnect it as a test to see if that corrects the 10 second delay in the 3 cylinders firing.
As far as that timer base working properly even though the numbers do not interchange, do make an effort to check the full spark advance timing while underway at full throttle to make sure it's accurate.