Timing my 1987 Mercruiser 3.0 with newer EST ignition

[islandboy47]

I bought a remanufactured Mercruiser 3.0 for my 2004 Bayliner 195 and installed the motor and it's running, but I'm trying to adjust the timing and I'm seeing different numbers everywhere online. I don't have the serial number for the motor, but the block number is 2770087. Everything except the flywheel and coupler on the outside of the long block is from the newer 2004 boat/motor, so I'm pretty sure that's the EST ignition. I'm most commonly seeing that the timing should be set to either 2° BTDC or 6° BTDC, can anyone tell me what the correct setting is, or how to find it? I'm afraid I'll ruin my motor by just guessing.

 

[alldodge]

The 3.0 and EST is a mix bag and all are based on serial number.
1 BTDC - Serial number break: 0L096999 and below
1 ATDC - Serial number break: 0L097000 - 0L0340999
2 ATDC - Serial number break: 0L341000 and above

I might go with 1 BTDC because this was also used during initial roll out, then watch and check plugs