3 hp Evinrude Won’t Idle

[hippovet]

I have a 1966 Evinrude Yachtwin 3 hp. I’ve tuned it up, new plugs, rebuilt the carburetor, etc. it has excellent spark and compression is 65 lbs in both cylinders. It is a clean motor that appears to have low hours. I’ve owned and worked on several of these great motors. For some reason this one won’t keep running at low speed. I’ve used both 50:1 and 24:1 oil:gas mixtures. The position of the slow speed needle doesn’t seem to matter. In fact, it runs best with the needle closed or almost closed. I’m not used to not having a high speed needle, like with this motor, but it seems to run okay at mid-to-high speed.

Any ideas or suggestions?

 

[racerone]

Does spark jump a gap of 1/4" or more on a test device ?-----Perhaps revisit carburetor since motor is not responding to slow speed needle.

 

[hippovet]

Does spark jump a gap of 1/4" or more on a test device ?-----Perhaps revisit carburetor since motor is not responding to slow speed needle.

Yeah, I’m thinking carburetor.

 

[Crosbyman]

drip chamber crudded ??? side channel feeding fuel to the LS circuit cleaned and blown...?
check closely for a very small feeder hole in the side channel
cam & follower adjusted properly ?

 

[Crosbyman]

see pages to adjust cam and follower

 

[hippovet]

I recleaned the carburetor and now it works fine.

 

[oldboat1]

For informational purposes, what did you do differently in carb cleaning. A lot of outboarders are tinkering with carbs this time of year.

 

[Crosbyman]

great news that you got going thanks for feedback

 

[rowerowe101]

I have a 1966 Evinrude Yachtwin 3 hp. I’ve tuned it up, new plugs, rebuilt the carburetor, etc. it has excellent spark and compression is 65 lbs in both cylinders. It is a clean motor that appears to have low hours. I’ve owned and worked on several of these great motors. For some reason this one won’t keep running at low speed. I’ve used both 50:1 and 24:1 oil:gas mixtures. The position of the slow speed needle doesn’t seem to matter. In fact, it runs best with the needle closed or almost closed. I’m not used to not having a high speed needle, like with this motor, but it seems to run okay at mid-to-high speed.

Any ideas or suggestions?

Try priming the primer bulb while it's idling.
If it keeps running, it's most likely the pump.
If not, and you said it runs well at almost closed slow speed needle it's likely flooding.
I would go over Carbuerators again via a pressure test. and spray the needle/seat area with water/soap to see if it bubbles indicating a leak.
Also-float level.

 

[racerone]

Most 1966 models ran off the gravity tank and no primer bulb.----But the poster stated that it be fixed now.