This is a multipart question:<br /><br />I have a 1991 Yamaha 115 V4 with a 19" prop that I run on a 1984 19' bayliner capri. The motor starts and runs well. Trouble starts at high rpm's. When I hit the throttle it takes off like a scared rabbit and hits 5000 rpm within seconds.<br />But then the motor starts to stutter and loses power and rpms drop to 4500. It will only calm down from stuttering when I drop the rpms to 3500. <br /><br />If I run at 3500 rpm I only get 18 - 20 miles per hour speed. Shouldn't it be 30 - 35 mph? Fastest speed I have been able to clock is 32 mph<br />on plate glass water at full throttle. I expected<br />at least 40mph. Am I wrong?<br /><br />I took the oil reservoir off and mix the oil with the gas in the tank due to running a 9.9 2 stoke kicker off the same gas tank. When the 115 is in the tilted position it leaks gas/oil into the motor well. When it sits it the water it slowly leaks gas/oil into the water. Is this normal?<br />It also tends to smoke heavily periodically when<br />starting and sometimes after a ski run.<br /><br />I have replaced gas line, primer bulb, and had fuel pump rebuilt. The only thing not touched on the engine is the carburators. Could they be the source of my troubles?<br /><br />I think the motor is in good mechanical shape and that all the above problems are interconnected but I am not sure where to go from here.
