1981 50 HP Evinrude - Linkage tweaking and "slop"

MartyTn

Petty Officer 2nd Class
Joined
Nov 3, 2002
Messages
108
This is the first time I've posted in a long time and thanks in advance for any pointers. I just purchased a 1981 Evinrude 50 hp outboard that has been pretty well cared for but needs some tweaking. Spark and compression are ok. So far, I've replaced the fuel pump and fuel lines from engine inlet through fuel pump and to the carbs. I corrected two air leaks in that process and the engine runs much better now at low speeds. Hi speeds and WOT are ok.

After correcting the air leaks I had to back the idle speed way back down to get it in the ball park again. I did this with coordinated small adjustments of the idle screw along with the throttle cable trunion. That got the idle doing well but left a gap of about an eighth of an inch between the throttle cam and roller. It ran much better at the lake on the test run even with that gap between cam and roller, but it just had quite a bit of off-idle lag.

Now I'm attempting to fine tune the cam-to-roller and I notice three things and would really appreciate some input.

1) When I loosened the cam roller and attempted to move it back into the cam (at neutral idle setting), the top of the roller aligns with the bottom mark of the two marks on the cam. The idle is set pretty low but idles well. Should the cam be farther forward (faster idle?) to bring the cam marks even with roller or would the new roller alignment be ok? I haven't touched the adjustment of the cam arm.

2) When bringing the throttle cable off idle I notice significant slop in the control arm itself at the pivot (9/16" bolt) point. Is this normal for an older motor, and if so, is there a recommended way (like adding a flat washer or two) to remove this slop? I have not attempted to tighten the bolt.

3) Also when bringing the throttle cable off idle I notice a little slop where the throttle cable meets the bottom of the control arm. Adding another flat washer where the nut goes on the control arm stud could probably help this. Is this normally done (or needed)?

Sorry for the long-winded post and Many thanks for any pointers!
 

Bosunsmate

Admiral
Joined
Apr 7, 2012
Messages
6,135
Re: 1981 50 HP Evinrude - Linkage tweaking and "slop"

1) The eights of an inch gap seems unusual to me
2) Normal, try tighten a bit, theres a big spring in there which can work that nut lose over time.
3)Ive a flat washer on mine. I find worn cables cause the biggest slop in the system
 

MartyTn

Petty Officer 2nd Class
Joined
Nov 3, 2002
Messages
108
Re: 1981 50 HP Evinrude - Linkage tweaking and "slop"

Thanks Bosunsmate for the help on #2 & #3. I created the eigth inch gap when I backed the idle back down after fixing the air leaks. Then I loosened the roller to move it back against the cam it now goes below the center of the two marks on the cam. I don't want to mess with the cam adjustment itself until I'm positive of what I'm doing. I have the OMC manual but it dosen't do a very good job IMHO explaining the linkage tuning procedure (or maybe I missed it). I also have Clymer and Seloc manuals on order for this engine. Most of my prior experience is with older Mercs and it was usually the combinatrion of all three manuals that it sometimes took to give me the nerve to move some things. :)
 
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