Chainsaw Repair

Whats the stories?

Steve,
If you dont want to use an oem 670 or 680 piston, here is an aftermarket one that should work;


Open up the muffler and put a walbro HDA-63 carb on it.

If you can find the Walbro HDA-45, it might be the better choice.  I know it is on the 8000.  It would depend on the size of the cs-680 intake runner.       

The 8000 came out with the HDA-45 which continued through the 8000p.  Then came the Echo color change to gray and the HDA-63 replaced the HDA-45.  Both the 45 and 63 have the 16.7 Venturi, but the throttle bore and choke bore on the 45 are larger.  8000's coming out now have an HDA-153, which is down to 15.08mm Venturi.     

Same thing on the 6700.  Original was the HDA-47 (16.7) followed by the HDA-76 and HDA-151 (both 15.08).  With the switch over to the CS-670 the auto choke carb became the HDA-203 (15.08).  CS-680 comes with the HDA-271 (15.08).     

Ebay Carl - Captain Never Sails - has the HDA-63 for $62.95 shipped.  Said he had 3 and when they were gone that he wouldnt be able to get any more.   Walbro works closely with Echo saws. developing fuel curves for their specific engine changes in their air pollution lab.  Specific carbs follow certain serial no. ranges, and when they replace one / obsolete the old one / your limited to what is on the shelves.   

     
   

Good job on the 680.  Echo uses the smaller carbs for quick starting.  There should be springs on the HDA-45 needle jets.  If theyre missing I can send you a set out of a rebuild kit.  If they are really wallered out use the blue loctite to tighten them up.  Just dont use a whole lot of it.