1984 60hp timing problem

[Speedwell69]

I set the TDC mark on the engine as described in the book I then set the full advance timing using a timing light with the plugs out and the engine cranking but the engine seemed to hold back and have little power when I tested it on the water so a friend was saying that it sounded that the engine didn't sound as though it was advancing enough so we adjusted the full advance again. The advance screw on the timing lever had been screwed all the way in pretty much after I'd originally set it with the timing light and then with the srew on the timing lever wound all the way out causing the maximum amount of advance that it's possible to gain in terms of the trigger moving and the engine seemed to run better. I find it hard to imagine that I could have got it that wrong when I set the timing mark up and that the movement from the adjustable pointer could be so far out that it required so much adjustment on the spark advance lever to get the engine to run better though still not as it should. The engine has had a new trigger fitted to it CDI 134-6453 and a new stator. Having used a spark tester on all 3 cylinders it shows all 3 are firing but the engine sounds like it's misfiring but the plugs also look like they have fired... Any ideas anyone


Thanks

Michael