Shift position disagreemnt

[Maine22]

2015 200APX engines with fly by wire. Starboard engine occasionally won't go into forward gear and a "shift position disagreement" shows up on my C10 gauge. Sometimes if I put it in reverse and then back in F it will work. Sometimes I go back to N and then F and it will work. Twice I have had to shut down engine and turn off battery and then restart and it will work. Ideas? Batteries tested good (load tested) and show 12.7 volts with engines off.
Thanks

[Naptown1]

Having similar issue with 2017 300hp (I run a single). On previous trips this year the engine seemed fuel starved and shut down (had an issue with collapsing priming bulb when we first got the engine when it was new) figured it was the same thing. Was able to get it restarted after priming it but I don't think that was really the issue. Didn't get any error messages though.

On my last trip it did the same thing while coming off a plane at around 3000 rpm. RPMs dropped to idle and ran roughly. Then started throwing errors about throttle disagreement. Then the fuel economy/rpm readings went crazy. It was telling me that I was burning 500 gph at idle and showing no RPMs. Then it started jumping all over the place with RPMs and fuel economy. Throwing messages about the trim settings changing without my changing them. Crazy stuff. Boat ran fine after a bit, though the RPMs only started to read accurately toward the end of the run in. Haven't been out since then. Figure I'll have the tools in place to disconnect the battery since that seems to be one of the "solutions" I've seen mentioned. Hard to wrap my head around a hard reboot being a viable solution for a $18k engine in a pitching boat, but in a pinch, I guess...

Really the first issues we've had with the engine, other than the crappy primer bulb. Interested to see where this question leads...

[Moonlighter]

If you search this forum on shift position issues on AP engines I think you will find some answers. I think I recall seeing something about a bushing getting corroded in the linkages for the shift position and causing it to bind up. That is all I know. I also recall seeing some of the same issues being raised on Outboard Specialties forum over on the THT forum.

Re engines stalling when they come off the plane, the first thing to do is GET RID OF THE ANTI-SYPHON VALVE on the fuel tank pickup. They are notorious for failing and causing that exact issue. Even if that turns out not to be the problem, it is a quick and inexpensive thing you can do yourself. I helped a mate who had a DF300 on his Striper, same issue, it would stall at idle but run fine at higher revs if you could keep it running and get the revs up. So I accessed the fuel tank takeoff fittings, undid the fuel hose, unscrewed the AS valve, took it to the workbench and punched out the little ball spring and seat inside the barb, and then reinstalled the empty barb fitting to the tank. Problem solved.

Your fault codes problems may also be voltage related. These engines are very sensitive to poor voltage/amperage and will not run well and will throw multiple codes if they dont get it. The fact that the engine played up as you slowed down - where engine alternator voltage decreases - and then the system started working better when you had run at speed for some time - may give you some hints about this potentially being voltage related, doesnt it?

So you would be wise to go over your electrical system carefully. Dont just “look” at connections - undo, clean, check for corrosion in the connectors, and tighten. Have a close look at the white wire - the battery sub wire, it provides power to the ecu and if it is loose or corroded Then you WILL have problems. there should also be a fuse in that wire so open the fuse holder up and give that fuse and holder a careful check over.

Check batteries - load test if possible.

[Naptown1]

Thanks for the tips and appreciate the detail. I'll look further in this forum as well as THT. Hopefully working from batteries to throttle, cleaning and tightening, will resolve the issue. I'll report back if we figure it out. Again, thanks for taking the time to respond. Enjoy your holiday weekend.