New or old? And what is "too long?". Does it hit things? Where?
Can it be pulled back into the boom and looped there? Would a more vertical feed to the magnet help. A drop further up the boom? A hanger? Maybe a lawnmower carburetor spring?
Regardless, one way to 'dress' a wire also takes up slack well. You need a dowl or phillips screwdriver shank, pen, maker or whatever,.
You dont.need.to disconnext a wire, just wrap it barber pole stlye, without gaps or overlapping, smooth tight. Then carefully slide the rod out, leaving a curly shape like an old.telephone cord. It will lack rebound but should flex in-line better overall and suck up some slack. ![IMG_20171223_223827 IMG_20171223_223827](https://ogrforum.ogaugerr.com/fileSendAction/fcType/0/fcOid/77030152589484326/filePointer/77030152593067053/fodoid/77030152593067047/imageType/MEDIUM/inlineImage/true/IMG_20171223_223827.jpg)
![IMG_20171223_223954 IMG_20171223_223954](https://ogrforum.ogaugerr.com/fileSendAction/fcType/0/fcOid/77030152589484326/filePointer/77030152593067054/fodoid/77030152593067048/imageType/MEDIUM/inlineImage/true/IMG_20171223_223954.jpg)
![IMG_20171223_223913 IMG_20171223_223913](https://ogrforum.ogaugerr.com/fileSendAction/fcType/0/fcOid/77030152589484326/filePointer/77030152593067055/fodoid/77030152593067049/imageType/MEDIUM/inlineImage/true/IMG_20171223_223913.jpg)