Slow Speed needle valve Lark 40 hp

[M.H.]

I have a 1970 Evinrude Lark 40 HP.
When I Go fast the needle valve thigthens itself all the way i guess due to Vibration.
When I Go back to idle It rund really bad or shuts off because It gets no fuel.
Is there any way to prevent this ?

 

[racerone]

Tighten the brass nut on the needle.----If the needle does not stay put install more packing.

 

[timguy]

Welcome. If it has been operated this way for quite some time you might want to reface the needle, check for damage on the needle surface/taper. I use a drill and a nice fine abrasive flat surface. You can also chuck it carefully in a drill press and hold a fine abrasive straight edge as it turns.

 

[M.H.]

Thanks for the fast Answers.
I will try it as soon as possible.