I purchased a 94 20ft Lowe pontoon a few months ago. It's a 70 hp 3 cylinder 2 stroke. The boat has not idled right since I bought it. After replacing the fuel lines, bypassing the VRO, cleaning carbs, new plugs, and replacing the head gasket, I did a compression test. Results: Top-115, Middle-145, Lower-145. I know this is a problem. I took it to a mechanic, said top cylinder is scored. So I got to work on it, ordered a manual, and took everything off. Took the powerhead to a machine shop and the top cylinder was bored .30 over. Middle and lower were both honed to polish them up. Ordered new piston head and all the gaskets I needed to replace the old. Put it all back together and threw it on the the boat. Compression test is now, Top-140, Middlie-135, Lower-140. All good. Mixed up fuel, 25:1, as indicated per manual. Took a couple cranks, but it fired up. Ran for about 30 seconds and then died. Boat runs fine above 1500 rpms, anything lower it stalls. I put the boat in the water to see if some back pressure would help, no luck. I did some tweaking while the boat was at the dock to the carbs. Started up, and same thing. I noticed that there is alot of fuel bubbling to the water surface, guessing its coming out of the exhaust. I was told a while back to back the slow idle screws on carbs out to 2 and a half full turns. The manual says 1 and an 8th turns. Do you think this is flooding my engine having the screws out 2 and a half turns? Also when i rebuilt the carbs, i replaced the floats and adjusted the drop as instructed in the kits. I noticed that one of the floats was a little sticky. Do you think maybe this float is stuck open and is contributing to the flooding? When the boat runs for its 45 seconds, I can hear a "ding" coming from the motor, but Im not sure exactly where it is coming from. Sometimes its immediately after the boat shuts off and sometimes its a minute or so behind. Im curious if this ding noise is the carb float sticking. Any suggestions you all have would be great.