25 hp top cylinder no combustion

25 hp 2 stroke Yamaha 2006 model. 2 cylinder 2 carbs. Top cylinder no combustion. Motor idles and runs at low speed but over half throttle it falls to its knees. Running and pulled top spark plug wire and no difference in running. Reinstall top wire an pull bottom spark plug wire and engine dies. Pulled both new plugs and top plug still looks new. Bottom has been firing an looks used. Pulled top plug and it is firing. Pulled air fuel mix plate on top carb and cleaned carb thoroughly as possible without removing. I was able to spray cleaner threw all areas and fill bowl. Put it back together an same problem. Any help would be great. I have done compression check an both cylinders are within 10 lbs.

sounds like upper cylinder is not getting fuel.pull fuel line on upper carb squeeze bulb look for fuel.if fuel pull carb and clean all passages throughly,bowl ,needles,set float etc.

Bowl is filling up but not going threw jet. Remove and cleaning thoroughly coming up. Thanks for ur help

Pull the top carb and break it all down. Don't be afraid to pull it and don't worry about replacing gaskets and such after pulling it as some may say. I've pulled 2 stroke carbs over and over and always put them back with the same gaskets used again with no issues. When you pull that little brass fuel jet blast carb cleaner through the jet and if you see any residue inside that little hole, run a piece of COPPER wire through it to clean it out. Don't use needles or pins or somehting else as you can leave a scratch in the brass that will attract more gumming. Copper is softer than brass so it will not scratch the inside of that orifice.