"Jeff... The ignition system,
"Jeff... The ignition system, without getting into the deep portion of it is: The battery must be in top condition, and be at least a 70amp hour battery to supply proper voltage to the pack, otherwise damage to the pack might occur. Voltage is being supplied to the pack and stored in a capacitor. The sensors in the timer base, trigered by the magnets at the center of the flywheel, supply voltage that in turn trigger a electronic switch in the pack which throws the stored voltage to the coil. The coil magnifies the voltage higher and transfers it to the rotor, then to the distributor cap, s/plug wires, etc.
You've stated that you do have spark on all four (4) cyls that will jump a 1/4" gap. It doesn't sound like you have a ignition problem.
The fact that you have made a gain in performance by cleaning/changing the h/s jet(s) in the bottom carb suggests to me that something is being overlooked in the fuel department. You made the statement "The rpm drop when pulling the #3 and #4 plug wires is not as much as #1 and #2". Just so we're not getting our wires crossed here, the cylinders are number as below when standing in back of the engine.
..........1
2
..........3
4
Cylinders #1 and #2 run on the top carb. Cylinders #3 and #4 run on the bottom carb. The lower response on #3 and #4 indicate that either there is something wrong with the bottom carb or it is out of adjustment on the adjustable slow speed needle valves. It's highly unlikely that two (2) leaf plate (reed) assys would be faulty or that the ignition would fail slightly on the two bottom cylinders.
If you're absolutely sure that the bottom carb is now completely clean, and that the linkages connecting the two carbs are as they should be (one doesn't open before the other), try adjusting the slow speed valves as follows.
First, if you haven't already, install new "red" valve retainers in the front of the carbs so that the needle valves can't viberate out of adjustment. These are OMC part # 315232. With these retainers, there is no need to have all that interconnecting wild linkage entwined between all four valves (with the red retainers, they won't move by themselves).
Gently seat all four (4) needle valves, then back them all out one and one half turn (1 1/2). Start the engine and set the idle to a point where the engine will stay running. Being in the boat, facing the carburetors, start with the top left, then top right, then bottom left, then bottom right needle valve.
1...2
3...4
Slowly in segments of 1/8 turn, turn the valve in and wait a few seconds for the engine to respond. Continue this action until you reach a point whereas the engine either spits back (sounds like a mild backfire) or it starts to die out. At that point, back that needle valve out approximately 1/4 turn. Within that 1/4 turn, you will find the smoothest setting. As you turn the valve in, the rpms will climb... drop the rpms (idle) to where you had it when you originally started this process, otherwise you'll end up with a screaming engine.
Repeat this process (adjustment) on all four (4) adjustable slow speed needle valves. You may need to repeat this process to double check yourself as at times, one cylinder may affect the other slightly. Good luck.
Joe
"