1991 or 93 25hp 2 stroke Evinrude running rough and won't idle.

Hoping to get some help and ideas here.

I have a 91 or 93 (can't fully make out the serial number) 25 horsepower Evinrude 2 stroke that is running rough and doesn't want to idle.

What I have done.

Fully cleaned and rebuilt the carburetor, replaced broken/original full pump with brand new fuel pump, replaced the spark plugs.

The motor will start quite easily and runs ok at mid range to high rpm's. However, when I try to throttle down and let the motor idle it either bogs down and dies out or I have to give it gas to keep it running. When running at low rpm's (almost at idle) it sort of backfires and pops sending smoke out of the exhaust.

I kinda want to order a manual for it, but not knowing the year I am having trouble finding the right book.

I have been considering running sea foam through to see if this helps, but wanted to get some opinions first.

Thanks in advance for your thoughts/help.

Max

Re: 1991 or 93 25hp 2 stroke Evinrude running rough and won't idle.

It may be a lean sneeze. Back the idle mixture screw out a little bit more.

Re: 1991 or 93 25hp 2 stroke Evinrude running rough and won't idle.

Cool I will check it tomorrow, and thanks for getting back to me so quick.

I played with that a little but didn't go much further than a 1/4 turn. It is also quite loose, as in, after adjusting and starting the motor, it has a tendency to loosen up some more on its own....

Re: 1991 or 93 25hp 2 stroke Evinrude running rough and won't idle.

When you overhauled the carb did you remove the small welch plug on top of the carb and clean the passages inside?

Re: 1991 or 93 25hp 2 stroke Evinrude running rough and won't idle.

The idle mixture screw should not loosen itself. In this picture #13 is a oring that keeps the needle sealed from air in leakage, and holds it in position.

Re: 1991 or 93 25hp 2 stroke Evinrude running rough and won't idle.

Ok to clarify, my dad pulled and overhauled the carb so I will have to ask him about the welch plug tomorrow. I have a feeling he left it alone though.

Also I was confused first thought you were referring to #1 when you said idle mixture screw. So the ims #13 is not loose, I have adjusted it, just did not know the technical term. I have adjusted it starting from 1-1/2 turns out all the way to 2-1/2 turns, 1/2 turns up, with little change in engine performance. I also tried dialing down and started at 3/4 out from seated, and then adjusted slowly up from there, again very little to no change.


#1 screw which is a jet correct? should be snugged down?

Re: 1991 or 93 25hp 2 stroke Evinrude running rough and won't idle.

Bringing it to a guy today or tomorrow, hopefully he can figure out what's up and it won't cost too much, results soon.