Logo
FULL SITE MENU

1997 evinrude 25hp backfiring

K

Kyle parmeley

New member
Hey so I’ve been having a problem with my 1997 evinrude 25hp outboard motor. When I first boat my boat a year ago it has ran about great doing about 21mph on a j16 Carolina skiff. Over time it has been losing its speed and backfire or cough when trying to accelerate. Now I’m only able to do 13mph before it starts to cough. My first thing was redoing the idle timing so I did. Toke it out I went 25mph for about 2 minutes it went back to coughing. So then I replaced my fuel pump, starter, spark plugs and rebuilt with cleaning my carburetor. I toke it out ran amazing. I went up to 26mph then after 15 minutes it went back to coughing again. The reed valves looks good but I just can’t figure out what’s going on. Any suggestions?
 
Last edited:
Kyle parmeley;710413]Hey so I’ve been having a problem with my 1997 evinrude 25hp outboard motor. When I first bought my boat a year ago it has ran great doing about 21mph on a j16 Carolina skiff. Over time it has been losing its speed and backfire or coughing when trying to accelerate. Now I’m only able to do 13mph before it starts to cough. My first thing was redoing the idle timing so I did. I Toke it out and it went about 25mph for about 2 minutes it went back to coughing. So then I replaced my fuel pump, starter, spark plugs and rebuilt with cleaning my carburetor. I toke it out ran amazing. I went up to 26mph then after 15 minutes it went back to coughing again. Then dies out when it’s in neutral The reed valves look good but I just can’t figure out what’s going on. Any suggestions?[/QUOTE]
 
It could very well be the spark is degrading as heat builds. If that's the case you will be best off using a DVA meter or DVA adaptor with multimeter to diagnose as the problem can be from a variety of sources...power pack, stator, timing base, rectifier, wiring. If you pm me with your email I will send you a PDF copy of an ignition troubleshooting guide for 2 stroke motors.
 
Welcome aboard the forum. Seems like spark related....did you try a spark jump test as Mr. Scott suggested? Try after it's warmed up and acting funny again. Let's start simple, eh?
 
Last edited:
Yes, you can do a quick check on the timing by inserting a pencil through the #1 spark plug hole and turning the motor slowly counter clockwise until the pencil is extended maximally. At that point the pointer on the flywheel should be pointing close to your published timing spec. If not close pull the flywheel to inspect the flywheel key.
 
Back
Top