Chainsaw Repair

There are two different 61's.  Most are the 'old style' with the 2 piece ignition and the cases that fit it (and the various top covers that fit those cases).  They also have the idle speed screw in the case.  Same cases used on the 162, 61, 66, and 266.

Then there's the late 61's that used the one piece 268/272 ignitions, the cases that take those ignitions, and the top covers whith the correct screw pattern for those cases.  These have the idle speed screw on the carb.  I have a set of cases from one of these.

A 61 is a 48mm bore saw with an open port jug and a smaller carb and intake.  Can't recall if the late 61's have the larger intake and carb as used on the 272.



This series is very open to parts swapping.  Depending on what cases you have, certain swaps take a bit more thinking.

As I read the IPLs, the "cutoff" point regarding one piece ignition, case, carb, muffler, top cover and much more is week 7 1991.
The top covers only changed shape (+ the placement of bolt holes) at that point though, the top cover didn't become orange before some time in 1993 (again according to IPLs (+ some info from @spike60)).

The new carb (HS-254) has the same 17.5 mm venturi as the 268/272 carbs, but it isn't the same one. I don't know what the difference is, or how the intakes compare - but at least the late production 61s lacks the air intake tubes in the top cover, that the 268 (all versions) and 272 have.