Reply To: looking for information on timing &synchronization for 1980 E15RCSD

[Don]

There really isn’t much involved with the syncronization of this 1980 15hp. Before we begin, can you tell me why you are concerned with this adjustment? Are you having a running issue?
There are not actual “timing” adjustments on this engine, WOT is controlled by the stop on mag plate linkage. There are not idle or pick up timing settings/adjustments.
So first, back off the little black knob on the port side of the engine so the mark on the black throttle cam is to your left (as you look at the engine from the top/front) to be sure the cam is not touching the throttle roller.
https://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1980&hp=15&model=E15ECSD&manufacturer=Evinrude&section=CARBURETOR+%26amp%3B+MANIFOLD
You can back off the screw (#20) if the cam is still touching the roller. It is very important that you ensure that the carb butterfly is actually closed at this point, just because the cam isn’t touching the roller does not mean the carb butterfly is closing completely, there could be some sort of mechanical issue (bent throttle plate or jammed throttle shaft) preventing the butterfly from closing completely. Unfortunately, there is no way of really knowing unless you remove the carb and actually look at the throttle plate. For the the sake of simplicity, let’s assume that the throttle plate is closing completely and there are no mechanical issues.
The objective is to have the carburetor butterfly just start to open when the mark on the cam lines up with the middle of the throttle roller linkage. The engine will run rich off idle if the cam picks up the throttle too late. The engine won’t idle correctly, or stumble/hesitate while accelerating off idle, if the cam picks up the roller linkage too early or the carb butterfly does not close completely.
The tricky part of this adjustment is realizing that there is slop in the roller throttle linkage, so just because the throttle roller starts to move at the proper time does not mean the butterfly is actually starting to open. Using a little alligator clamp on the throttle shaft helps show when the throttle shaft actually starts to move/open. So, with the throttle cam mark in the middle of the throttle roller, turn #20 inward gently until the throttle shaft just starts to move/open. Sure, it is pretty tough to get this adjustment spot on, but it is not that critical to ensure it is “perfect”. It is better to have the throttle open just a bit too late than too early…Having the engine run a little rich off idle is much better than having it run lean and stumble while accelerating off idle, or refusing to idle because the throttle plate is cracked open slightly at dead idle.
Once you start the engine and let it warm up, you may want to adjust the low speed needle slightly and reset the idle speed using the black know on the left side of the engine pan.
Again, I will ask why it is you are concerned with this adjustment…Are you having a running issue with this engine?