1987 Evinrude 50 hp missing at idle

[Sarrre]

Hey,

I got an Evinrude 50 hp which is running very bad at idle speed. It misses very often, and it also revs up and down intermittently.
When putting it in gear, I need to quickly increase speed to prevent it from stalling, and as soon as I get it up on plane it's running perfectly. Please check videos below. The first one is in idle speed, and the second video is in high speed. Do you have any advice how to troubleshoot? I have already inspected the carbs, and I couldn't find any obvious cloggings.

https://www.youtube.com/watch?v=9_B1iy5JmhM

https://www.youtube.com/watch?v=y7TjdpfUKjY

 

[ondarvr]

It's still running lean at an idle, so the carbs are either still a bit dirty (not uncommon) or aren't adjusted correctly (if they have adjustment screws).

​There are very small passage ways that unless a good deal of effort is made don't frequently get clean thoroughly enough.

​Also check the compression just so you know it's good.

 

[desertratz]

looks like one carb is running lean at idle, probably has something clogging the idle circuit.

 

[juno pierrat]

try loosing the screw on the top carb that connecting linkage rod goes too, and make sure the cam roller is not touching the cam on bottom carb, now both carb throttle plates should be completely closed, tighten the screw on top carb and adjust roller and cam to lightly touch, the middle of the roller should aligned with the lower line on the cam, i had same lean sneeze (miss) but finally got sync and sync right, now it idles all day,
if you've had the carbs off and apart for cleaning but haven't removed the core plugs, under the core plug are two or three very small holes that need to be cleaned, that is part of the idle circuit.

 

[juno pierrat]

bump , any luck Sarrre