Is this Demon just junk or am I just junk at dealing with it?
I have a 650 Speed Demon. It used to be the primary carburetor for my car, and after getting tired of screwing with it, I changed it out. Since I've been getting some quarantine projects done I decided I'd try and get this thing reset to factory and see if I can at least make it a decently-working backup for the shelf.
Background: This was bought used, and it has never worked "right." I have never been able to get the car to idle without being stupidly rich with this carburetor. It has been rebuilt several times by people who actually know what they're doing (certainly not me haha) and it just never doesn't stink the place up at idle, and it always had an issue with wanting to stall after stabbing the throttle and quickly backing off.
Motor: 340 that's actually 340 inches, X heads, MP Purple Shaft .474 cam, headers. The jets that made this carburetor somewhat useful were 68s in the primaries and 74 in the secondaries. 727/3200 stall converter/3.91 gear. Car is just under stock weight.
When I was messing with it tonight, I pulled up the Demon setup page, just to verify what I knew it was supposed to be set at. There should be .020" of the transfer slot visible below the throttle blades, on both the primary and the secondaries. I can get the .020" set just fine on the primaries when simulating the throttle return springs in place. The secondaries are a totally different story. When simulating throttle return springs in place, I get about .060" of slot visible, and cannot for the life of me get any less visible transfer slot, even with the curb idle screw not even touching the linkage - they just don't close any more than this. There aren't any obstructions in the way, the butterflies do not appear bent at all. They just don't close.
Are the butterflies adjustable on the Speed Demon? If so, how? I tried removing the screw and locknut on the butterfly shaft, but stopped because I didn't want to break anything. Should I just throw this pain in my *** away? Anyone want to buy a pain in the *** Speed Demon? I really hope there's something absolutely stupid that I'm missing because I've hated this carburetor for so long and I'm blinded by my own rage.
I have a 650 Speed Demon. It used to be the primary carburetor for my car, and after getting tired of screwing with it, I changed it out. Since I've been getting some quarantine projects done I decided I'd try and get this thing reset to factory and see if I can at least make it a decently-working backup for the shelf.
Background: This was bought used, and it has never worked "right." I have never been able to get the car to idle without being stupidly rich with this carburetor. It has been rebuilt several times by people who actually know what they're doing (certainly not me haha) and it just never doesn't stink the place up at idle, and it always had an issue with wanting to stall after stabbing the throttle and quickly backing off.
Motor: 340 that's actually 340 inches, X heads, MP Purple Shaft .474 cam, headers. The jets that made this carburetor somewhat useful were 68s in the primaries and 74 in the secondaries. 727/3200 stall converter/3.91 gear. Car is just under stock weight.
When I was messing with it tonight, I pulled up the Demon setup page, just to verify what I knew it was supposed to be set at. There should be .020" of the transfer slot visible below the throttle blades, on both the primary and the secondaries. I can get the .020" set just fine on the primaries when simulating the throttle return springs in place. The secondaries are a totally different story. When simulating throttle return springs in place, I get about .060" of slot visible, and cannot for the life of me get any less visible transfer slot, even with the curb idle screw not even touching the linkage - they just don't close any more than this. There aren't any obstructions in the way, the butterflies do not appear bent at all. They just don't close.
Are the butterflies adjustable on the Speed Demon? If so, how? I tried removing the screw and locknut on the butterfly shaft, but stopped because I didn't want to break anything. Should I just throw this pain in my *** away? Anyone want to buy a pain in the *** Speed Demon? I really hope there's something absolutely stupid that I'm missing because I've hated this carburetor for so long and I'm blinded by my own rage.
