ox66 idle issue

[MechanicMike]

Have a 2000 Yamaha 150 ox66. Going on our 7th season with the boat and motor. The boat has an issue when idling in neutral. Have a digital gauge. When the engine warms up at idle, the tach fluctuates between 6 and 7. When at 6, sometimes it will stutter a little and puff smoke from the exhaust. Very rare case it will stall and start right back up. Never has an issue starting cold or hot, or idling in gear. Cold it will fire up to High Rpm and idle back down once it warms up. Been through the whole fuel system numerous times including recently doing stats, l/p pumps, clean vst and regulator screen, cleaned 02 sensor and passages, fuel filters etc. Replaced plugs. The 02 sensor is only a few years old. I clean it and the passage every year as maintenance due to an issue I had years ago from lack of maintenance by the previous owner. Had the injectors cleaned and flowed. All checks good. Have even run it on an auxillary fuel tank with no change. Problem is delayed after running the boat at speed until it idles for a bit. If I kick the Rpms up a little in neutral to 7 or 800, its fine. In gear its fine as well. Seems like it may be loading up a bit after an extended idle. The only things I have yet to try is a link and sync and checking the oil rod adjustment. Any ideas would be much appreciated

Thanks
Mike
Thanks Mike

[scofflaw]

Manual says 730 rpm +/- 30. So it shouldn't be in the 6's. Mine acts similar, not a big deal for me. Link and sync always a good thing to do or turn your idle screw up a bit

[FabricGATOR]

I have a similar pair of LX/SX150TXRY and one of mine was doing that same thing. If not exactly, darn similar. I too went through most of the fuel system, plugs, VST, fuel pressure, ignition wires, coils... When I was running to the fishing hole or returning to dock, I would power back and while maneuvering at idle, that engine would rough, then die, and always at the most inopportune moment.

Mine turned out to be the stator as finally determined with the help of the folks here. The stator hardly ever goes bad, and that was how I gained all the experience in cleaning, maintaining, setting, adjusting, and testing. In the end it was determined that my stator was faulty. A factory fresh new one was beyond my wallet at the time, yet I was able to find a salvage one and rolled a natural on the dice.

Check everything else first.