I have a 2002, Yamaha 150 HP, 150xtra on a 2002 Bay Stealth that has been sitting for about 18 months with fuel treated with Sta-bil. I'm trying to get it going again and I have a power problem. The engine will start and only keep running with intermittent choke about every 1-4 seconds. Out of gear the engine will run around 1800 RPM with no choke. In gear, in the water, I can only get about 1100 RPM with choke every 2-4 seconds. I drained all the old gas down to where the pump bulb was sucking air. I put in 10 gals. of plus grade with Sta-bil. The engine performance did not change and my 25 HP Kawasaki mower runs fine on the removed gas from the boat. I checked the plugs and they had some fuel/oil on them. I cleaned them and reinstalled. I pulled the air box to check for any bird nests or other obstructions but it is all fine. The carbs look clean and everything moves easy and smooth.
What next???
What next???