Motor running a little rough.

[Frogger]

Hey I have got a 2002 Mercury 25hp four stroke that runs rough at idle. You guys have any ideas what could be wrong with it! I might change the oil and spark plug to see if maybe that's the problem.

[ShilohRed]

Just a guess but sounds like it needs running. My Yamaha 25 does that if it has been sitting for awhile.
But after running it. The motor will clear out and run fine. I had to have the carb cleaned 2 years ago.
The low idle jet is so small in these 4-strokes that they stop up easy
Pete

[papasage]

try this site for help . the 4 stroke is to new for me

http://www.themarinedoctor.com/cgi-bin/YaBB.pl

[abarkley]

i bet shiloh is right, but check and make sure your motor isnt sucking air in somewhere in the fuel line. that happened to me and i couldnt figure out why it would it run rough every time i cranked it after it sat a couple hrs or so.

[Matt Smith]

Get a small gas can and put about two gallons of fuel and can of SeaFoam in it. You can buy SeaFoam at any auto parts place. Run the motor AT THE LAKE for about 15 minutes and shut it off. Let it sit for about half an hour and start it back up. Do this two or three times. That should clean your carb up.

If your carb is so gummed up that it won't let the motor run, you'll need to disassemble and clean it. Also, if your motor is a two stroke, you'll need to add the appropriate amount of two stroke oil to the fuel.

[boatman44]

If you haven't had it serviced, take and get the carb's syncronized, I synch. honda's all the time and it makes a biggg difference. hope this helps.

[willsjwills]

try fresh fuel