No announcement yet.

Help with Rotax 503 Mid 4000 to 5500 RPM Lag ?

  • Filter
  • Time
  • Show
Clear All
new posts

  • Help with Rotax 503 Mid 4000 to 5500 RPM Lag ?

    Prior to the following i was having no troubles runing this motor.. Until I pulled Carbs apart for cleaning, replaced fuel pump with new and disconected/re-connected Dampening box.Motor starts first pull has full response upto 4000ish then from here to 5500 its sluggish and slowly responds. From 5500 onwards full power and response is regained. Carbs were reassemblied correctly and have been checked to ensure, fuel pump correct type and installed correctly as recomended. Dampening box polarity is the only thing Iam a little unsure on if i have correct.. Will it harm system to reverse ? Motor has not been ran for about a year or so.Please if there is there anything that sticks out to those with 503 experience your help would be appreciated ?

  • #2
    Found the Problem.. Defective ignition suppressor box.Next question ? On the wiring diagram it shows in the box a Diode and what looks like a Cap or resistor thats all..Does anyone know what it contains ? and could i just make one ? $200 for new. Its incased in resin I will attempt to dig out components to see. Thanks kc


    • #3
      Might be a condensor. I have a whole armature plate here if you want it. I don"t know how good it is I have never used it but it is complete. Throw me a few bucks for postage and it is yours.