I am out of ideas on this problem and would appreciate some advice! The symptom is that when putting the boat in gear (forward or reverse) the engine will intermittently rev UP all by itself and settle down as well... enough to knock someone off the platform! It seems to have gotten worse as now when it revs up the driver needs to pull the throttle back to stop it. Fuel being used is the same I have used for a long time and from the same gas station. Other than this issue the engine/boat runs fine. I haven't been able to correlate to engine or ambient temperature, whether it is the first or second set, etc..
Here is what I have done to no avail:
- replaced both fuel filters (drained FCC)
- Set timing to 8 (latest spec as far as I can tell)
- checked fuel pressure - rock solid at 60psi
- Checked for DTC codes - none
- replaced distributor cap and rotor
- replaced the potentiometer/throttle position sender
- replaced the throttle cable
- verified the problem is there even if ZO is off
- tested with several settings of throttle cable to potentiometer "home" position
Anyone have any advice on how I can correct this problem????