I recently replaced my spark plugs. Took the boat out using leftover but treated gas from November 2021 and it ran great. Idled well; started just fine and ran well.
My last outing referenced above was early last week. During that outing, I finally used most of my old gas from November 2021. So, when I went out this past Friday I put in 15 gallons of 87 octane, which I treated with mercury fuel treatment and Mercury cleaner which I’ve also used each time I’ve ever gassed up the boat. Early on, the motor started, idled and ran well. Then after fishing for about 90 minutes, I went to start it and it started but idled horribly. It would not stay idled-would die after sputtering for a few seconds. I attempted to start it several more times and got the same result. Then, I started it and while it was sputtering, I quickly put it in gear and hit the gas. This allowed me to get going and once I was above around 1800 rpm it ran perfectly fine. Also idled fine after the run. Fished for 30 more minutes, the tried to start it and had the same sputtering idle. Got it going the same way.
Then the remainder of the evening, I had no issues.
Think the fuel cleaner broke something free and temporarily caused a fuel flow issue in the pump, fuel rails or an injector? I had no warning beeps. Engine serial number is in my signature.