I have a 1989 Johnson 60hp which had an infrequent ignition miss problem with warm engine and middle or high rpms. After a lot of investigation (that's another story) i finally found the power pack defective. I replaced the original #583748 power pack with a Sierra #18-5766 type (which is labled "Prüfrex OPP511" from Germany).
Now the ignition works correctly on all three cylinders, the miss is solved. But I found the spark timing 8° (7° after TDC instead of 1° before) delayed referred to the original power pack and the engine behaves like that. Is this a known problem? Have I simply to readjust the spark timing/spark advance and that's it? Or is something wrong with the new power pack? To me it seems that the original power pack triggeres on the first edge of the timer base pulses whereas the Sierra part triggers on the zero cross a little later. There is just the angle offset and no time delay betwen timer base pulse and sparking because with higher rpms the ignition angle remains constant and does not move towards late.
Thanks for comments!
Now the ignition works correctly on all three cylinders, the miss is solved. But I found the spark timing 8° (7° after TDC instead of 1° before) delayed referred to the original power pack and the engine behaves like that. Is this a known problem? Have I simply to readjust the spark timing/spark advance and that's it? Or is something wrong with the new power pack? To me it seems that the original power pack triggeres on the first edge of the timer base pulses whereas the Sierra part triggers on the zero cross a little later. There is just the angle offset and no time delay betwen timer base pulse and sparking because with higher rpms the ignition angle remains constant and does not move towards late.
Thanks for comments!
