intermittent spark

[smitgj]

I hope someone can help me out!! I bought a 2000 Katana on the weekend. The owner fired it up for me while I was getting my helmet out of the car. I heard it start and it started up fine, took it for a ride, ran great. I trailered it home and it wouldn't fire up. I thought I flooded it so I charged the battery and later it fired up. Ran great, shut it off and then it wouldn't fire up again. I took off the tank pulled a plug and they were horrible. I changed them and left #1 out and turned it over, SPARK!! put it in and fired it up, ran great. Shut it off, put the tank back on and it wouldn't start again. I pulled the tank off again and pulled #1 and #2 spark plug since they run on seperate coils and there was no spark! I took a voltage meter and on the #1 and #4 coil I have 11.7 volts at the top terminal but no voltage at the bottom terminal and on the #2 and #3 coil I have 11.7 volts on the top and bottom terminal. I am getting frustrated and if someone can give me an idea if it is that #1 and #4 coil because I am not getting voltage on both terminals or if it could be something else. It seems to be intermittent and when it runs it runs great it doesn't cut out or misfire. Please help.

Thanks,
Gary

[jamesm113]

sounds like you already narrowed it down - the #1/#4 coil is faulty.

[kevin2502000]

To determine if it is the coil, unhook the wires to the good one and hook them to the bad and see if it has spark. Or you could do vice versa.

[rexazz2]

how is the gap on your plugs?
Mine will run on two cylinders , runs but not well
I had issues with moisture and ethanol fuel, thought I lost a coil
I put in some Sea Foam fuel addative in the tank and ran her and issues went away

BTW if your battery is not strong you are going to have starting and firing issues

[smitgj]

Okay! I just replaced the #1,#4 coil and I still have no spark? Any other ideas?

[kevin2502000]

do like I said, switch the wiring around, might be the pick up coil.