Re: Evinrude Lightwin problems

[cajuncook1]

Have you isolated which cylinder is dropping? If so, which one?

Have you performed a cinder drop test?

While running, remove the spark plug wire to the top cylinder. If the motor continues to run then the bottom cylinder is firing and get enough fuel. If it dies, then your bottom cylinder is suspect. Replace the spark plug to the top cylinder nice and snug. While it is still running remove the spark plug wire to the bottom cylinder. If the motor continues to run then the top cylinder is firing and get enough fuel. If it dies, then your top cylinder is suspect.

If both cylinders pass the cylinder drop test, then your focus is now on fuel delivery.

There was a poster about a year back with a 1966 Evinrude 18hp that had very similar issues that you are having now. It took a year of on and off testing to get his motor right. Both his cylinders pasted the cylinder drop test but did not run well past mid throttle and would run rich or like on one cylinder. His motor would run all day long idling and start very easily. When he would run past mid throttle it would bog down and then, as instructed, he unplug the gas line like to run the carb dry. The engine would smooth out and run great for a few seconds.

Even though his carburetor was set correctly and totally clean it still ran very poorly above mid throttle. Replaced the fixed jet office with a new one and it ran perfectly. It seems the fixed jet may have gotten reemed or damaged along the way. That jet is metered precisely and if it is cleaned and the hole is enlarged, then a rich running condition can result. $5.00 for that little part.

The only thing that is different here is the gasket for reeds was found to be damaged and you stated the reeds were fouled and possibly not functioning correctly.

Just to make sure, are you running the motor on the gravity fuel tank above and not off a fuel pump from an external tank.