1956 Evinrude engine Clunk Noise 15HP

[Kevin60181]

I just gave this a complete tune up, coils, wires, plugs, points, etc. Along with new seals, O-rings in the lower gear case and a complete new water pump.
The engine ran OK, but after the above. It?s running great with higher RMP?s and smother.
Now, mostly when it?s cold and at idle, there is a loud clunk noise and the engine almost stalls for a second as the engine jerks. It happens now & then.
The clunk noise is a lot louder than in the video. Once the engine is warmed up this rarely happens, nor does this happen when in gear. ????
Open to your ideas and suggestions!
Here's the Video on You Tube:
http://youtu.be/Cl1gm5tUS2g

 

[Daviet]

Re: 1956 Evinrude engine Clunk Noise 15HP

Nice looking engine.
That is called a lean sneeze, open the low speed needle, the top one, 1/8 to 1/4 turn open and see if it doesn't cure the problem.

 

[HighTrim]

Re: 1956 Evinrude engine Clunk Noise 15HP

If opening the needle counter clock wise about 1/4 turn does not help, ensure the low speed needle packing nut is tight, with proper packing washers, and there are no other air leaks anywhere, such as in the fuel line, connections, carb gasket, etc...