Hi!

I have some questions about the timing advance on my 1997 Mercruiser 350 Bravo 300HP. In the manual it says that the initial timing should be set to 8 BTDC @1800RPM, with scan tool in service mode. That is OK!

But when i remove the scan tool, the ignition jumps between 10-14 deg @650RPM. Is that normal?

BUT, maximum ignition advance is 40 BTDC @4000+RPM!!. Is'nt that wierd?

Yes, once you release from the base timing mode the ECM takes over and you will see the timing all over the place as it's constantly adjusting based on the myriad of sensor inputs. Mine does the same thing.