87 evinrude 25 hp acts weird

[Cwyatt]

Motor always starts on first couple of pulls but only runs on the bottom cylinder for the first 20 minutes or so. Then second cylinder cuts in and she runs great for the rest of the day. I suspected ignition, so I replaced plug, plug-wire, and coil...no help.<br />My brother says the reed valve could be carboned-up.<br />Anyone ever heard of a stuck reed valve?

 

[12Footer]

Re: 87 evinrude 25 hp acts weird

Yes, I have heard of that happening. Get a compression gauge and check the compression.<br />Then get a can of ValveTect outboard Decarb Cleaner, Seafoam, or other carbon-blaster from the nearest marine supply house, and use it according to intructions on the can.<br />Retest the compression. It should increase dramaticly. If not,(and comp is below spec), it may be time to pull the head,and see what be goin-on on the piston-side of things.<br /><br />

 

[Dhadley]

Re: 87 evinrude 25 hp acts weird

Check the spark when it's cold. That's the easiest thing to do to get you headed in the right direction. It can't hurt to run engine tuner thru it at long as you follow the instructions.<br /><br />Good luck!