I have an '86 Mercruiser 170/ Alpha One 19" pitch prop that stumbles and sometimes pops back through the carb when you accelerate under load. (pulling up skier, going up river)I just did the electronic ignition conversion and that's about it(new to me boat). This problem was happening before to conversion but it idles much better now just stumbles and bumbles sometimes. I am planning on doing plugs and wires and new coil. Since that probably hasn't been done in a while, what next? Rebuild the carburator? Maybe timing? Any help would be great.