Re: 55hp model 5571 only did 7 knots
Ahhh! That's an oldie but goodie. Someplace in the late 60s I think. If it starts easily and idles well, that tells you that the ignition system is probably ok. However, if the timing rod is not connected or broken, you will advance the throttle with no timing advance. this will make it sound "funny" for lack of a better description and will not put out power at partial to full throttle-- The timing rod runs from the top of the tower to just under the flywheel on the bypass side. Just look at it It will either be there and connected or not. There is not enough adjustment on it to get you into trouble. That's on the magneto ignition. I think battery ignition with twin coils is the same. If you have points and they are set to significantly less than .020 this will affect timing and speed. If that's ok, then check fuel delivery. A poor or clogged (sediment bowl) fuel pump can supply enough fuel for idle and the engine may run beautifully but with higher speeds and increasing demand for fuel, it will starve. It will sound like its going "flat" --bog down with no power. If this is what it sounds like, check the complete fuel system from tank to carb. If the engine sounds like it is revving high with no water speed, then you need to check the prop hub to see if the rubber insert is slipping. mark the prop and hub near where the shear pin goes through. If the marks are not aligned after running in water, the prop needs to be re-hubbed. Check plugs. Usually bad plugs show up in failure to start or poor idle but bad plugs and wires can arc at higher rpm giving a miss with lack of power.
