Topic: one side of coil is blowing main fuse ..why ?

[cadaver]

OK this is my problem ...i have a 76 550f i have a new battery,  bought a diff engine that wasn't frozen and then tryed to get spark ..well no spark. so now i threw in a diff pair of sparkplug coils...so now this is my new problem that trickled down ..when i hook up one coil it turn the key and the emerg switch ..everything is good and yes spark ..so i hook up the other and switch the emerg on ..boom fuse blows ...hummm so now i do the K.I.S.S to it ..keep it simple stupid....so i throw in another fuse for the side that works and run that one ..got spark ..now i unhook that one and try the other one ...boom blow the fuse ... now is the other side that is blowing a fuse bad ? do i half to take it back from the place that i bought it from ?  all help would be nice ...even if you think i should try a diffrent why would help me out ...I'm stuck .

[TwoTired]

You are using replacement coils  not stock, right?  Do you know what the primary resistance is?  Stock is 5 Ohms.

Are you getting 12 v to each coil?

Are you using points?  If so, are they both closed at the same time? (Are they set correctly?)

What size fuse are you using?

[cadaver]

well I hooked up my old coils and hooked up the wires and low and behold my fuse isnt blowing and im getting spark at all 4 wires..now I gotta tell the guy that sold me them that one is bad and see what hapens thier ..so if anyone has that kinda problem ..that means that one of your coils are bad ...hehehe some times new isnt better than old .