Re: 1974 70hp Evinrude won't come up to speed
Sounds something like a rev limiter in a car, i've never heard of such a thing on an outboard, specially 1974, do they drop (RPM) and then stay steady if you leave the throttle? Perhaps your carburator is loading up on fuel and then burning it off and dropping back down. What would happen if you throttled it up a bit and left it for a few seconds? <br />the other thing which sounds similiar is what i call a "flapper problem" sometimes rubber hoses will start to deteriorate inside and will peel up enough to catch water or fuel, this usually only happens when a high volume of liquid flips the rubber flap up closing the hose off, causeing the rpms to drop until that flap drops back down allowing fuel again, might be a long shot but i've seen it happen on **** tubes before, only plug with a full load, then unplug when throttle down, check your lines
Welcome to iboats!<br /><br />As posted, there could be some junk floating around in one or more bowl that is plugging a high speed jet when you try to rev up...do you know when the last time the carbs were overhauled? Hoses in good shape....still soft and plyable?<br /><br />Have you tried squeezing the primer bulb to see if the engine picks up when the problem occurs? If the engines revs pick up, this would indicate a fuel flow problem to the carbs...possibly a bad fuel pump, lose connections, dirt in the fuel tank. There is a fine mess screen on the front of the fuel pump where the fuel comes into it. Remove the cover and check it. Make sure it's clean.<br /> <br />Also, on the reverse of starvation, take a look at the carbs and see if any are spilling out fuel while running which would indicate flooding.<br /><br />Any history about the engine you can add would help....is this a new engine to you, did this problem just start?
