Low Compression

Discussion in 'Bubba's Outboards' started by Gamblen, Aug 29, 2009.

  1. Gamblen

    Gamblen New Member

    Messages:
    450
    State:
    Kansas City, KS
    When I bought the motor for $50 the guy said it runs and runs well. I buy cheap motors alot. How come people always say they 'run well'? lol.

    Anyway it has solid state ignition. Tested all (entire) the electrical and replace the charge coil because it would not fire. Ran compression test, top 80 psi. lower 60 psi., that scared me, but what the heck, the guy said it 'runs well'.

    Got it firing long enough to find out the water pump worked. Rebuilt carburetor and the motor ran good for about 30 to 50 run hours. Then it quit running. The compression now in each cyl. is 50 psi..

    Lower cyl. spark plug (new) has apparently never ignited the fuel even though its getting spark to the plug and fuel to the cyl.. Upper cyl. is igniting a fuel mixture by seeing residue on the new plug.

    THE QUESTION: Will a outboard motor run on 50 psi. compression????

    1980 Evinrude, 7.5 H.P., Model E8RCSS, E0001259. Thanks, Ron
     
    Last edited: Aug 29, 2009
  2. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Yep it will run on 50 but will be weak and hard to start. Those are famous words it ran good last time out.:smile2: As for it not burning fuel on one cylinder I would find out why and get it to or it won't run to far that way. I would say that is why its had the different readings to start with. Swap the coils around and see if the cylinder fires then.
     

  3. Gamblen

    Gamblen New Member

    Messages:
    450
    State:
    Kansas City, KS
    Thank you Willard. I'll get a new starter rope for it and go back to work.
     
  4. Gamblen

    Gamblen New Member

    Messages:
    450
    State:
    Kansas City, KS
    DUCK TAPE, huh,

    Went to the hardware store today and got a new starter rope. Took the top of the air cleaner off because its easier to string the new rope on. When I did I found a big old piece of duck tape stuck in the carburator throat. I had put the duck tape on the Air Cleaner because when I bought the motor the Idle adujustment knob was missing and there was a big hole in the Air Cleaner where the knob was suppose to go. Motor runs find now, when warm starts on a half pull. Thanks for the help, Ron
     
  5. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    You trying to stop mud daubbers from getting in or you trying to stop dust on the river from entering.:smile2: Glad you found it. I would still do a good decarb on it and it may pull the compression up a little.:wink: