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Evinrude 6 hp help....

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  • Evinrude 6 hp help....

    I have a 6hp 70s evinrude outboard that starts on the first pull but doesn't have the power it used to last season. Here's what I have done so far:

    -tested compression and each cylinder is at 100 psi

    -checked for spark and each cylinder is firing

    -cleaned the carb and put the rebuild kit in it which made no difference at all.

    -gapped the plugs to 30 thousands which made no difference

    -closing the choke somewhat does nothing for rpm so it doesn't appear to be a lean condition.

    Is there anything I am missing????? It is baffling me.....

  • #2
    Old, poor quality fuel; are you using fresh fuel ? Checked the condition of the fuel filter ?


    • #3
      Check propellor hub for extreme wear (if it has a rubber bushing inside); check throttle linkage for a slipping screw which won't allow full push-pull actuation; check fuel filter for obstructions and fuel pump for out-put; check for carbonization/fouling on plugs; run new fuel with SeaFoam in it.


      • #4
        Yea, sounds like a fuel issue you may have a restriction somewhere. The fuel lines on old motors get ridged and can kink, this can cause restrictions. Just a trouble shooting guess here, good luck.
        07 C-Dory 25 Cruiser



        • #5
          Thanks for the help guys. It is really strange, I was playing with it last night in a run tank and it rearly runs really good until you put it into gear. Then, it sounds rather sick and it acts like it wants to run good, it just doesn't. I am going to pull the carb again to check the float level and if there is something I am missing. I will look for kinks Jay as I haven't - there may be one. Sayak, your tips are great and I checked them. The carb and linkange are working just as they are supposed to, as is the prop and everything in the lower unit as last season I changed the oil, lubed the prop shaft, and put it back together. It is a power issue of sorts. It has fresh fuel, new plugs, good fuel flow, and what appears to be good spark.


          • #6
            Since you are having difficulties once you put it in gear have you checked the gears and lube in the lower unit? Maybe something is amiss in the lower unit which is causing an additional load on the motor that it is not prepared to handle.


            • #7
              I don't know what the compression ratio is supposed to be for the e-rudes, but 100psi computes to a compressio ration of 6.7:1, which sounds low to me.

              I'd recomend pulling the lower end and inspecting it. See if when you put it in gear it turns over freely, or is binding somewhere.
              Those that are successful in Alaska are those who are flexible, and allow the reality of life in Alaska to shape their dreams, vs. trying to force their dreams on the reality of Alaska.

              If you have a tenuous grasp of reality, Alaska is not for you.


              • #8
                Originally posted by breausaw View Post
                Yea, sounds like a fuel issue you may have a restriction somewhere. The fuel lines on old motors get ridged and can kink, this can cause restrictions. Just a trouble shooting guess here, good luck.
                Check the gas line from the fuel tank to the carb... look for old dry rotted gas line that could be sucking air.../John


                • #9
                  If everything else checks out as others have suggested above, try the following (BTW, +1 to leaking fuel lines - just replace it if in doubt as fuel line is cheap. be sure to use USCG approved fuel line).

                  1. Decarbon the engine if you haven't already done so. Lots of crud builds up over time and has a huge impact on performance. See following link:

                  2. If it's still low on power, check your reed valves. A quick way to tell if they are sealing is to remove the carburator cover, run the engine, and hold a piece of cardboard near the inlets. If it is spitting fuel/oil onto the card board, the reed valves need to be changed.

                  Hope that helps.

                  PS - 100 psi compression is fine. If the cylinders are off by 10%, then it's time for a re-build.


                  • #10
                    Thanks for all your ideas. I checked the reed valves, everything else you guys noted, and found nothing out of whack. However I did notice something while working on it. When pulling on the pull start it has spark in both holes. When running (not me, the engine) one can pull off the plug to the top cylinder and it makes no difference in how it runs. So I put a tester light on it to see if it is at least firing and it is, just not very consistently or strong. It is nothing like the other one. I will pull the flywheel when I find a puller that will fit the little guy and give you an update. I think there are points and a coil pack back there. I bet one of them is shot.......Once again thanks for the help, ideas, and support. I think there is hope for it


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