2014 Yamha FXHO Rough Idle issue

[Chester123]

Hello all.
I've got a 2014 FXHO and it has developed a rough idle, and wondering if anyone has some insight to what the issue might be

About the ski:
175 Hours
95% of use is in saltwater
I use it for ocean fishing and trolling for salmon, so at least 30-40 of those hours are at idle/slow speed.
Ski is flushed and cleaned after every use. I finish off the flush with Salt Away
Regular oil changes.
I run normal pump fuel that has ethanol.
New spark plugs last summer at '100 hour service' at the dealer.
Has run perfectly until this recent issue.

The issue:
Had a great day of fishing on the ocean and right at the end of the day (after a 30+min drift with engine off) I started it up to go in and it began to have some problems. It would run for a second then shut off. Took about 5 tries to get it running and only stayed running after giving it some throttle. Then it was rough on the idle, almost as if the engine was missing. Drove it around a bit and it seemed to be ok, and then crossed over the bar and took it to the ramp. My guess it was a fuel delivery issue or a spark issue.
Back at home I cleaned and flushed it but it was running fine on the hose. No issues.
Thought maybe the problem was solved but figured it was a good time as any to run some injector cleaner through it. I picked up some quality fuel system cleaner (BG Products. Good stuff!) and added to my half full tank. Took the ski to the river to burn through the fuel and at it dock it started idling rough again. Again, after some throttle and keeping the RPM's above idle it seemed to run ok. Took it for a 20-30mi run and burned through most of the gas. Got back to the dock and the problem seemed to be gone.
I thought about replacing the spark plugs but my local shop was out of stock. (ordered them online, should be here in a few days) Instead I double checked them and they all looked clean and in good condition. The gaps we're a little off, 1 to 1.1mm, so I re-gaped them all to 0.8mm.
Started it up in the driveway on the hose and was great. No issues.
This last weekend I took it out on the water and the issue was back.....straight away at the boat ramp it was idling rough. I drove it around a bit and it seemed to get a little better. Then I'd sit for a while with it off. Start it back up and it would be rough again.
I then hopped in the water next to the ski so I could listen to the engine better and had my girlfriend start it. It seemed like there was some rattling noise or a bearing type noise coming from it. Noise was more from the back towards the intake/impeller area, if that makes sense. Was hard to pinpoint. Then when she would rev the engine, the noise would go away. As the rpm's dropped the noise and roughness came back.
So, it seems the issue only comes from when the ski is in the water and under load. It also only seems to be there when the engine is cold, as it seems to idle fine after it's been running awhile.

Any ideas on what it could be?
Thanks!

[Chester123]

New plugs showed up today. Gapped and installed them and took it to the boat ramp. Problem solved! Still didn't seem to be the smoothest idle its ever had but maybe I'm being over critical/hyper aware...
Idled great and no odd noises. So I think this one is solved.