rough running at low speeds

[dmwerwie]

My 1986 Evinrude V4 140hp runs rough right off the dock. When I get past 1/2 throttle, it's great. The motor runs smoother at slow speeds when warm. Is there anything that can be done to have it run smoother when cold?

 

[JGKoenig]

Re: rough running at low speeds

I had close to the same problem with my Chrysler 140. It turned out to be the diaphram in the fuel filter. If it gets a small pin hole in it, it will run rough at low RPMs and good at higher RPMs. Its just a piece of rubber and can easily be replaced.