I have a "new to me" 95 90HP salt water Evinrude. She ran "like a top" once I got her going after sitting for a couple years. Had her out three times and burned thru a tank and a half fuel. Developed a chirping noise in the control box. It was suggested that I put 50:1 in the fuel until I figured why the chirp is there. Sounded good to me so, I put the necessary oil in the fuel. Today, after replacing the worning horn, she wouldn't idel. After numerous attempts got her to idel, but everytime I put her in gear she died. After about another 1/2 hour "trying" got her to the point where I could get her run "at speed", after "stumbling" a bit, but that only lasted five minutes. Then she just wouldn't run once I put her in gear. When ideling She'd give a puff of blue smoke and rev up for a second or two then go back to a half harted idel. Had the wrong plugs. Had QL82YC and learned I need QL78YC which I have now. Drained the tank and got some black sludge out that looked like "black water" under the fuel. Tried to get it all but not sure.<br /> Tank is now full of new fuel, new plugs and she still puff's a blue smoke ball and the engine rev's for a second or two then goes back, where she was.<br /> Does it sound like a fuel/oil problem? Now that I have new fuel and plugs I'm trying her again in the morning to see if she'll get me shrimping. If not she's going in the shop. At $75 an hour, was hoping to fix her myself, on a retired budget.... Thanks for any thoughts!!!!!!!!!!!! Ron