Johnson Evinrude 85 HP runs rough

It's around a 1980 85 Hp and it smokes a lot sometimes, as well as can take a number of cranks to start it. I am going to take it in for a tune-up, but is there anything special I should have checked on it, that would case it to do that? ONce it gets warmed up, then it's fine and seems to run fairly well.

i think if i get it tuned up, it will go a little faster also.

Re: Johnson Evinrude 85 HP runs rough

It will need a thorough de-carbon treatment for a start, then get the compression reading and write them down cylinder-by-cylinder so you have a ready reference if you have the problem again.

The early 85 HP motors don't have recirculation check valves, thus it is more critical that they run at the proper temperature. You need to know that the thermostats are working properly and keeping the engine at the correct temperature.

Use the best TCW-3 oil that you can afford. The synthetics produce far less carbon and smoke because they have a higher flashpoint and are more highly refined. That reduces the plug fouling as well. Be sure to run Carbon Guard or similar product in your fuel all of the time.

Finally, be sure to use the J/E dealer recommended spark plugs, a full-sized water-separating fuel filter, and keep the motor propped to run 5,800 RPM at WOT.