PDQ OWNERS FORUM

I am posting this so that it might help someone else in the future. My starboard engine has had a problem reaching full rpm at wot. At first it was intermittent and would come and go but recently it was mostly gone but full power might kick in for few seconds. I don't have tachs but you could tell by the sound and you could tell because the boat speed jumped 1/2 knot when it kicked in.

I rebuild the carb, checked the fuel pump, ran it on an auxillary tank with a new hose, primer bulb and fitting and changed plugs twice. That's when I noticed that the new plugs were came out black. It seems like I was running rich so I checked the thermostat and found it closed and would open when heated but when I looked close, I saw the thermostat rubber plunger had a large tear. I changed the thermostat and found that the plugs now came out clean but still no full speed. I did a shock treatment with yamaha ring free and also did a decarb with Seafoam. Still no full speed.

So now while running at WOT with the cover off, I began to manipulate the wires under the cowl where they plugged (or are spliced) into the wiring harness and that was it. As I moved the wires away from the cowl I got full speed and I could replicate the problem by moving the wires back and forth. So something is shorting out at WOT? I cannot explain in but maybe someone else can. Could it be the kill switch wire and a partial short?

I plan to unplug, clean, replug and wrap the whole affair with extra insulation.

My guess would be the pulser coil wires, that sets the timing for the ignition and could definitely cause those symptoms.