1959 Evinrude Lark 35hp - Won't stay idling.

Joined
Sep 15, 2015
Messages
14
I have a 1959 Evinrude Lark that won't stay idling using the controls on the handle. I can get it to drop RPMs significantly by turning the lever to the "start" position, but if I go to "slow," the engine just dies.

At high speed, the engine works fine. I was able to get 25.3mph out of it in my 14ft aluminum boat on a windy day with rough water, so it definitely runs, but starting it can be a bit annoying.

The throttle linkage appears to have been tampered with before I bought it, so I'm not sure how it should be adjusted. Any thoughts on that? The idle control knob near the base of the handle is all the way down. Not sure if that's working correctly. The low speed fuel adjustment needle is set to 1.5 turns away from gently seated and the carb is pristine clean. I rebuilt it recently.

Any thoughts?
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Well, that collar is a guide at best. Don't take it as gospel. Have you set the needles on the water? 1.5 out from seated is the static setting, then you fine tune from there, starting at WOT with the high speed needle, then down to idle in gear with the low speed. If you need help with this let us know.

What is the compression?

What plugs are you running?

What is the quality of spark?
 
Joined
Sep 15, 2015
Messages
14
Well, that collar is a guide at best. Don't take it as gospel. Have you set the needles on the water? 1.5 out from seated is the static setting, then you fine tune from there, starting at WOT with the high speed needle, then down to idle in gear with the low speed. If you need help with this let us know.

What is the compression?

What plugs are you running?

What is the quality of spark?

I read the tutorial posted here on how to set the needles. The high speed is set. The low speed is at 1.5 turns away from seated and hasn't been touched. I still need to do more work on the low speed setting. FYI, I did rebuild the carb.

Compression was 90psi on a leaky compression tester (o-ring wasn't seated) when I bump started it using the electric motor.

Unsure of spark plug brand. Some champion plugs I believe, copper. The engine runs fantastically at WOT. I managed 25.3mph with some pretty choppy water in my 14ft aluminum boat. Quality of spark...not sure how I would quantify that, but I did get the flywheel off and checked the coils, and both appear to have been replaced at different times. I checked both primary and secondary coils with a multimeter in addition to the spark plug wires, and everything looked good. Points are spotless, and I'll replace the spark plugs soon just in case since I don't know when they were last changed.
 

scout-j-m

Chief Petty Officer
Joined
Jul 31, 2009
Messages
636
Pretty much any size outboard with any type of ignition system should be able to jump a 1/4" gap. I think the ideal gap is really more like 7/16". To test that you can use those cheap adjustable ones they sell at auto parts stores for around $10 each.
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
As stated, you need an open air gap tester. After a while, you can determine the quality of spark by the sight and sound of it alone, when it jumps the 1/4" gap.

7/16 is a bit big for a magneto ignition, that is the gap setting for newer, electronic ignition motors.

I would first ensure that the points are polished (you cannot tell if they are dirty by looking at them, trust me), and you have a good, quality spark that will jump 1/4" with a bright blue ZAP!!

Then, I would set the carb up, on the WATER, not in a test barrel. High speed first, then low.
 
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