2009 210 No throttle after shifting to neutral?

[Boats Bros]

We had a nice weekend down here in Texas so I took the boat out for a cruise. It took a while to start (because I replaced the fuel filter and forgot to prime / fill the FCC) but when it finally did, almost all of my gauges weren’t working. Tach worked fine, only the screen on the speedo was working, not the needle though. Shift it into gear and take off, and I’m thinking that’s odd, but the boat drives like normal. Shift into neutral for a second, then go to take off again and nothing. The boat would idle forward and backward, but not gain speed. Check engine light comes on.
So I turn the boat off, and then back on. Drives fine for the 1st time under throttle and then back to only idling after going through neutral. So we drove around the rest of the day without ever taking it out of gear and drove fine for a few hours. Any ideas what I should be checking first? Boat is a ZR409 with 150 hours.

[NautiqueJeff]

I would GUESS potentiometer. But hooking up to Diacom will tell you for sure.

https://nautiqueparts.com/potentiome...-sensor-2007-/

[jpwhit]

It could be coincidence, but I'd start diagnosis assuming it's not a coincidence that you lost your gauges and have the throttle issue all happen at the same time.

Assuming it's not a coincidence, I would think you have an issue with bad grounds somewhere. Ground issues could disable the gauges and also cause the engine ECU to get unhappy about all kinds of sensors that are referenced to ground including the pedal position sensor.

Diacom would be extremely helpful in figuring out what's going on. But while Diacom is a very useful tool, it's not going to "tell" you answer. But it'll give the data to help figure out the problem if you understand the boat's systems well enough and have enough experience using Diacom. The caveats about Diacom are because I hate to tell someone to buy a very expensive tool after they have a problem, and then they feel like it didn't help them enough.

Diacom is something that it's much better to buy before you have an issue and spend a good bit of time playing with when you can connect it to a boat that's working correctly so you can learn the tool and get experience with what normal operation looks like. Once you have a problem, you're probably better off paying someone that's experienced with using Diacom rather than buying it at that point.

If the two issues aren't related, then you probably are having gateway issues and an issue with the pedal position sensor that just happed to occur at the same time. But if you do have to replace the PPS, then the engine ECU will have to be reprogrammed due to the original PPS part no longer being manufactured. And that will have to be done at a dealership or you'll have to remove the ECU and send it to PCM.