2018 AR210 running rough below 3k RPM

[HawaiiBreeze]

This is just a last ditch comment as another boater, DonJohns, was recently experiencing odd twitches in his boat motor (would run fine at certain rpm and then sputter) and it turned out to be the battery (maybe a grounding or voltage fluctuation). His replacement of the battery solved it.

 

[Coryd]

Update - Finally figured out the issue and it ended up being a major repair. The starboard engine continued to intermittently run rough with strong vibration under 3k RPM but seemed to run fine at higher RPM. Took the boat out again a few weeks after posting this and when I went to throttle up, felt a thump, heard a loud pop, and then lost propulsion on the starboard pump. The engine remained running and was actually running very smoothly at that point. I noticed the pisser for that engine was no longer working so I immediately shut the engine down. Since the boat is still under warranty, I didn't tear into the pump myself as I figured the issue was probably something fairly major.

Took the boat to Cycle Springs for diagnosis and repair on 2/16/22. They determined that it was a driveline failure as a result of the splines shearing off of the driveshaft. Considering both driveshafts had been replaced a year earlier as part of another major repair, I was a bit surprised. They mentioned that they have seen this on rental boats with a lot of hours. My boat does have 430 hrs but only around 100 hrs on the driveshafts. Anyway, they decided that the entire driveline needed to replaced, including the intermediate bearing and pretty much the entire pump housing except for the nozzle and reverse gate. It took Yamaha a week to approve the warranty claim and, of course, took almost a month to get all the necessary parts.

The repair was completed last Friday and the boat seems to be running well so far. The transducer was also bad and they replaced that as well, which I now have an issue with the speedometer being off but that's a discussion for another thread. Anyway, just wanted to provide an update on this in case this type of issue comes up for anyone else. Also, if you're on the fence about whether or not to purchase the YES warranty on a new Yamaha, do it. My warranty has paid for itself at least 4 times over.

 

[HawaiiBreeze]

So glad to see that you are whole again. Think I'll be getting under my boat this coming weekend and check my drive I line. In the water I have a vibration at idle more like a resonance vibration/sound but I'm gonna pop off my ride plate and grate and take a look.