1977 4HP Evinrude Running Rough

[Buddy]

I have a 1977 4hp Evinrude that I use on a sailboat. The motor is in good condition and usually runs well. Last week I was using it and after it had been running for about 30 minutes, it began to sputter as if it was running out of gas, but the tank was almost full. I was able to nurse it along and after 10 minutes or so it smoothed out and ran ok. Any thoughts on the cause and what I might check to prevent more problems?

 

[Fouled Plug]

Re: 1977 4HP Evinrude Running Rough

If it were me, I'd probably check and replace the plugs if necessary, Then maybe drop the carb bowl and check for gunk, flush lines and filter, make sure fuel was fresh. Start with the basics and hope for the best!

 

[Diesel]

Re: 1977 4HP Evinrude Running Rough

I had a little 4hp Evinrude "Light Twin" for a while that did the same thing just after I got it. Cleaned out the fuel system and made sure the tank vent was good, replaced the plugs. Solved the problem, motor ran fine for over a year.