I have a '94 Evinrude 40 that I've owned for about 7 years. It has never been reliable and a few years ago a mechanic convinced me to disconnect and stop using the oil injection system, which I did. <br /><br />My current problem is that she starts and runs fine until I try to accelerate onto a plane and then it starts surging. She will begin to speed up and then drop down. This continues in an irregular pattern. It never manages to run fast long enough to get on a plane. <br /><br />We have taken off and rebuilt the carbs and found the high speed orifaces clogged. I thought that solved the problem until I ran her and the surging started again. The book I'm using says surging problems are often the fault of the fuel pump but the pump seems to operate fine unless it is cutting out at high speed. <br /><br />I still have the old VRO fuel pump for the oil injection system which my local dealer says is expensive and he would have to order one. I hate to replace an expensive fuel pump to find that the problem lies elsewhere. <br /><br />Any ideas or suggestions would be appreciated.
<br /><br />Failing fuel pump is one suspect, but not the only one by a long shot.<br /><br />What is happening is that your engine while accellerating and under full throttle is burning fuel faster than it is being supplied to the carbs.<br /><br />Air leak or restriction in the fuel lines from the tank. A friend who is supposed to be a hotshot wrench replaced an engine because of this. His fuel line was pinched between the bilge pump and the hull. 