rebuilt my engines top end

The manual called for 5 degrees, I tried 7 and 8 and ten and it kept on flooding and finally I said the heck with it and put on 15 degrees and it fired right up. I thought it was a fluke so i waited for a while and came back to the boat and she fired right up again. thanx to all that responded.

If you are having a flooding problem, it probably has nothing to do with your timing. It's probably time for a carb rebuild kit. Flooding can be caused by stuck or worn needle valves, bad (or improperly adjusted) floats, or a blown powervalve (if it's a Holley). You could also get a mixture that is too rich after a cold start if your choke thermostat is adjusted too tight. Did you replace the fuel pump? If you have higher fuel pressure, you will need to reset your float levels.

ALSO... Unless your engine has very low hours, or you have recently replaced your timing chain and gears, your factory timing setting may not be optimum now.