Topic: 1952 Evinrude Lightwin 3hp (Carb adjustment) – Antique Outboard Motor Club,Inc

This topic has 18 replies, 9 voices, and was last updated 5 years, 11 months ago by cesarp35.

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May 10, 2018 at 5:39 pm #9881
cesarp35
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Well guys i couldn’t resist in purchasing my 3rd Old Evinrude, i now have 57 18hp, 57 7.5hp and now 52 3hp, my question is on this 52 3hp, it had been stored outside for the past 20 years so it needed a good clean up, after installing new coils, points, condenser, plugs, wires and carb clean the motor fired right up, however I’ve seen you tube videos where this motor idles at very low setting (on the SLOW) throttle lever marking on the hood, this motor idles ok at higher setting, i’ve backed the low speed needle 1-1 1/2 turns and the high speed 3/4 turns out, but when adjusting the low speed i find myself turning it back almost all the way to the right in other words until the back up starting point, same with high speed needle. The needle valves appear to be in good condition, when turning the low speed knob there really isn’t any adjustment idle response until i tighten up almost all the way, same with high speed. Any help or suggestions is appreciate it!
May 10, 2018 at 6:56 pm #75705
Mumbles
Participant
The needles may have been over tightened at one time deforming their seats in the carb but that’s why they are adjustable, so you can dial it in. On these carbs, the high speed needle does affect fuel flow a small amount to the low speed circuit to so jumping back and forth adjusting the needles should give satisfactory results. The high speed needle may want to be on the rich side a bit to help the motors low speed running and coming off idle.

Throttle synchronisation has to be spot on for these motors to run right as does good compression for them to idle right down. Any air leaking thru worn bushings on the carbs butterfly shaft will also affect the idle.

Here’s some more info on them at this link and a parts PDF.

http://www.outboard-boat-motor-repair.c … cedure.htm

Attachments:

Evinrude Lghtwin 3HP 3012 Parts Manual.pdf
May 10, 2018 at 9:08 pm #75714
frankr
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US Member
About that throttle synchronization: It is a bit different. Look at the bottom edge of the tank support ring, where the speed control slides left and right. Near the left end of that swing, there is an indentation in the tank support ring. When the speed control lever is under that indentation, the carb butterfly should be closed and just barely ready to open as you slide the lever toward fast.
May 11, 2018 at 3:45 am #75764
cesarp35
Participant
I was just concern about doing the same and over tightening as it seems like i’m pretty close to the end (stopping point) it seems like just about less than a quarter turn away from needle valve stopping point and i’m afraid of setting to close where vibration might eventually damage the needle, i’m hoping that the carb needle port isn’t enlarged or damaged
May 11, 2018 at 10:31 am #75770
jerry-ahrens
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US Member
For proper adjustment of the mixture screws, you should adjust the high speed (bottom) needle first. Run the engine full throttle on the boat, turn the high speed needle slowly closed till the motor bogs down, then open it slowly till the engine speeds up and runs smooth. NOW, you can do the same with the low speed needle… when you slowly close the needle, the motor will actually idle up a bit when you get to the point of being to lean. Then, open the needle slightly till you have a smooth idle. if you have good compression, your motor will idle all the way down to the ”slow” range.
May 11, 2018 at 6:21 pm #75794
cesarp35
Participant
Got it, i’m going to give it a try, thanks to all who responded!!
May 12, 2018 at 2:38 pm #75841
The Boat House
Participant
https://www.youtube.com/watch?v=x2IJs2PWcbk
May 12, 2018 at 3:06 pm #75843
seakaye12
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US Member
quote cesarp35:

when turning the low speed knob there really isn’t any adjustment idle response until i tighten up almost all the way, same with high speed. Any help or suggestions is appreciate it!

Did you by chance remove the welch plug on the top of the carburetor? Removing that not only allows for thorough cleaning….but it also allows a visual inspection of the "fit" of the needle in it’s seat. It is right there.

You can also clean the idle system when the carb halves are taken apart. The idle feed is the small hole in the upper body (The gasket has a matching hole of course…). With the slow-speed needle removed….place a finger over that opening and spray carb cleaner into that hole in the upper-half of the carb….and observe the tiny holes in the carb throat….right behind the throttle plate. You should see the carb cleaner spraying through each of those holes. (This would be with the welch plug in place…)

Another thing I recently learned the hard way is to check to be sure that the needles installed are the correct ones. Sometimes people swap over damaged needles with one that "is almost the same"…..and that causes various issues in running that can have no apparent cause.

Chuck
May 16, 2018 at 2:49 am #76066
cesarp35
Participant
Hey guys just wanted to update this thread, well after dissembling the carb again and let it sit in degreaser for 2 days i assembled and start it up and it was doing the same thing, running pretty crappie, i couldn’t adjust the carb correctly, i didn’t think about checking the spark plugs since i had just replaced them recently when i replaced the coils and points a few weeks ago. Well i did a spark test and wouldn’t you know it one of the new spark plugs was bad, i replaced the spark plug with one of the older ones that i took off the motor when i bought it and it started and ran really good, i was able to adjust low and high needle and bring it down to a slow idle, sucks all this time i thought i had a carb problem and it was a damn bad spark plug, well live and learn. Thanks for all the help guys and here’s a video of this old 52, not pretty cosmetically the sun has taking a toll on it but at least it’s not all dented up.
https://youtu.be/bhsjo0_M4B8
May 16, 2018 at 3:16 am #76071
david-bartlett
Participant
Cesar,

That runs nice! Well done. I love those 3hp twins.
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