40 HP Evinrude fuel delivery

Discussion in 'Boat Tips' started by okie catfish hunter, May 3, 2006.

  1. okie catfish hunter

    okie catfish hunter Member

    Messages:
    49
    State:
    Ponca City, OK
    I have a 40 HP Evinrude that sat for 3 years. We went through the fuel system last year. The fuel pump was shot. The carbs were gone through with new kits, all fuel lines were replaced. The previous owner had had a problem with the 2 cycle oil pump which caused damage to the engine that has since been rebuilt. This scared him enough that he started premixing the gas instead of relying on the pump. The local boat shop wanted close to replacement cost of the pump to special order a kit for the pump. To get the boat running last year since we didn't need the oil pump we installed an electric pump designed for a small vehicle. It runs fine up to about 3/4 throttle. At full throttle it runs great for a few seconds and then starts surging like it is starving for fuel. It ran fine before it sat for three years while I was replacing the deck on the boat. Is an electric pump just not a good idea? Does a fuel pump designed for just gasoline have trouble with premix?Am I maybe overlooking something else? It is a 4 PSI pump but I'm not sure of the volume. What volume is required for this engine? Any ideas would be greatly appreciated.
     
  2. DittmeRhino

    DittmeRhino New Member

    Messages:
    39
    State:
    Missouri
    I have a 90 hp Mercury that experienced a very similar problem. The Shop ended up draining the fuel tank, cleaning it out, then they replaced the fuel pickup assembly. They also changed the primer bulb as an additional safety measure. It now runs fine.
     

  3. catseeman

    catseeman New Member

    Messages:
    1,189
    State:
    Indianapolis, Indiana
    I have replaced 3 primer bulbs in 2 years. the new gas has chems that hardened the bulbs. At full throttle the check valves inside bulb reversed and would not let gas flow to carb. Figured this out 10 miles from ramp and truck. the first time ti happened.