Mariner 15W 15 horsepower. Manufactured between 1977-1985. S/N 662 L130029.<br /><br />This outboard engine was stored indoors over the winter and is now refusing to start. All fuel lines between the tank and the carb have been checked and are clear.<br /><br />When pumping fuel the ball goes hard and remains so, even after pulling on the starter cord many times. The fuel is reaching the carburetor. I can remove the fuel line from the carb, pull on the starter cord and fuel is being ejected from the open end of the fuel line, thus assuming the crankcase pressure operated fuel pump is in running order.<br /><br />The carb has been opened and emptied a number of occasions so I can confirm fuel is getting past the needle valve into the bottom bowl of the carb. The float does not seem sticky and moves freely with no restrictions at all while re-assembling the carb. All jets and passages within the carb look clear and free from buildup of grime etc. All gaskets are leak proof.<br /><br />With the spark plugs removed and the engine turned over I can feel a good head of pressure at the spark plug holes. Using thick rubber gloves I can confirm that a strong spark is being produced by both plugs (that test hurt until I wore the rubber gloves, highly reccomended, lol).<br /><br />Now the annoying bit. If I put a few drops of petrol directly into the cylinders via the spark plug holes, immediatly replace the plugs and turn the engine over, it roars into life, runs sweetly for a few seconds and then stops once its used up the tiny amount of fuel used to prime the cyclinders.<br /><br />To me it seems the fuel is not leaving the carb, and upon dismanteling it yet again the bottom bowl in the carb is still full.<br /> Before I hit upon the idea of priming the cyclinders, I could pull on the starter cable many times, remove a spark plug and there wasnt really any strong smell of fuel in there.<br /><br />I've used up all my mechanical abilities on this problem and need a few ideas of things to check out. I read somewhere that it may be the a dodgy contact on the 'kill' switch but then somewhere else mentioned that if I've got a good spark at the plugs then this cant be the case.<br /><br />One last point that may be a clue. The fuel was recentluy contaminated with water which was then pulled through to the carb. Needless to say the engine didnt even try to fire up. New fuel tank, all fuel lines, filter, pump and carb emptied, dried etc. And still no luck unless I prime the cylinders manually with fuel, the only time I've heard the engine going this year so far.<br /><br />All the best from a sunny Scotland, and hoping someone can direct me in the right direction.
<br /><br />If there isnt enough vacum to pull through the fuel air mixture, any advice on how I can test this or potential clues for me to look for?<br /><br />All the best from a misty isle off the north west coast of Scotland.<br /><br />Mark R