The Mighty Mac77 Has Spoken!!!
All hot and sweaty now. It's hotter than heck outside, and I've been pulling over that Mac77. It has outstanding compression and good spark. Got it to run on a spraybottle of mix down the throat. Primer doesn't work at the moment, and the carb's not pumping either. Sounds healthy though. Just gotta get the carb sorted out.
That carburetor was designed by committee. Part of it is in the rear handle (throttle "gate", venturi, "venturi orifices") while the rest is in a "pump diaphragm chamber" below the rear handle. The primer pump is yet another sub assembly mounted between the tank and the "pump diaphragm chamber".
I think somebody used the saw as a bicycle or go-kart power unit at one time. Thankfuly, they didn't cut any castings or drill any holes (unlike some chainsaw bike repower butcher jobs I've seen). They probably lost the bar adjuster assembly during the saw's tour of duty as a bike mule. Maybe that's when the outer bar stud disappeared too. There was a bicycle sprocket sandwitched between the chainsaw sprocket and the outer washer sprocket washer. Took
that out before starting the beast...
Does anybody make diaphragms and primer rebuild kits for this saw? I hope so. Now, I could luck out and have the diaphragms and such be in good shape, with just some crap clogging things up. I'm not holding my breath though. As for the primer..........I don't see a rubber duckbill type check valve listed in the IPL (unlike other primer Mac carbs I've seen). There's only a "check valve body" listed. In the IPL pic it looks like a hex-headed plug. Don't know for sure what's inside...
what I need for the saw is:
1)Bar adjuster/clamp plate assembly. Whole thing's gone. RandyMac may be able to hook me up with one from a 4-30.
2)Sheet metal bar plates. May be able to rob the 35A for these.
3)One bolt for the handlebar. Just gonna source it at the local HW store.
4)Carb diaphragms. I pray that I don't
realy need these....and can get by with just a cleaning...
5)Primer rebuild bits....see #4...
6)Rubber fuel cap check valve thingee. Tis gone...
7)One bar stud+retaining nut. Probably will go local for the nut. May be able to rob the 35A for this stud. PO replaced this stud with a bolt...