Re: 1968 18 hp evinrude

[jerry-ahrens]

I suspect that your low speed needle is out of adjustment. If the low speed needle is open to far the engine will immediately flood out. Not open far enough will cause an immediate bog. Turn the low speed needle in GENTLY untill it’s seated, then back out 3/4 of a turn. The low speed needle should be no more than 1 full turn open. This will give you a starting point, and allow you to run the engine in a barrel. Allow the engine to warm up completely, then at idle, slowly turn the adjustment needle in, untill the engine coughs, then back it out [slowly] untill you obtain a smooth idle. If the carburetor has been rebuilt by someone, chances are they used an aftermarket carb kit. I would suggest going to an Evinrude dealer and get the OEM kit and do it the right way. Follw Don’s advice and make sure that high speed jet is clean. If the low speed needle turns easy and won’t hold an adjustment, you can try gently snugging up on the packing nut, located right where the needle enters the carburetor. This may just fix your trouble.
Take a look at the carburetor bowl gasket. You can see it protruding out, where the two halves of the carb bolt together. If it’s a darker brown color, then you may be ok. If it’s a brighter yellowish color, then it’s aftermarket and your carburetor should be removed, cleaned and rebuilt with an OEM kit. I might get yelled at here, but I hate aftermarket carburetor kits! They have made me chase my tail many times trying to track down a weird running problem.