Newly rebuilt GM 153ci, mercruiser, 120hp, 1987 model. Backfiring
through carb. I suspect that I've gotten the spark timing off some
how. I have the manual and I have the firing order in the correct
order, but I'm still getting the backfiring through the carb. When
assembling the engine I double checked that when the slot on the pulley
was @ 0 the #1 piston was at TDC and installed the distibutor with the
rotor button pointing toward the #1 plug wire. The engine doesn't
start. I put new plugs, wires, dist. cap, and POINTS. I don't have
any experience with points. What I did was, put the .022" feeler gauge
between the gap while the point was at the open position and adjusted
accordingly.



So my question to anyone is: How can I verify 100% that my timing is
at least close enough to fire the engine?

How do you adjust points?

Thanks