Need help with a Mac 740

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StihlNAlberta

ArboristSite Member
Joined
Feb 12, 2012
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Location
Canada's West
I picked up what looked like a nice Mac 740 not knowing who did what before me. I changed the fuel lines and filter. Rebuilt the Walbro Flatback, then swapped in an HL 63 to see if that might help. I can get it to fire for about 30 seconds then it just floods itself out and dies. It won't rev up just sits at a high idle even when the throttle is engaged, choke on or off. Then can't get it restarted until if dries out overnight. I pulled the flywheel off and looks like someone removed the points and threw on a universal ignition module. Just wondering if anyone has any insight as to if this may be an ignition problem?? Do the coils or modules die out slowly? Oh yeah, I opened up the Tillotson and was gonna rebuild the carb but everything looked new so I left it. Saw has lots of compression.

I'll post some pictures. Any Mac guys could provide some help that would be awesome. Seems like I'm going in circles.
 
Oh yeah, I plugged off the impulse line with a golf tee but it didn't seem to matter with or without it plugged.

Thx!!
:crazy:
 
I'm no expert but prefer points when possible on these old Macs. Also maybe you will have to reset the inlet needle adjustment tang. And is the plug new?
 
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