distributor

I am trying to resolve a problem with the apparent lack of power with my 1927 Series 36, EDL. I have resently overhauled the engine and while it starts great and seems to run fine at low speed and without any strain on the engine it looses power when put under any kind of a strain. even with advancing the timing manually it still does not seem to have much power. I have removed the distributor cap and there appears to be a problem with the rotor cap returning to “fixed”” position. Other wise there is some play in the rotor cap and I am guessing that it is about 6-10 degrees of movement. It seems as thought the centrifugal advance spring(s) might be broken. I will take it apart tomorrow but I am wondering if anyone knows where you can buy replacement springs? Any assistance would be appreciated. Thanks.”