Help, no spark: By zbuck (Read 6,989 times)

[zbuck]

139 engine 4T. I checked the coil primary resistance and it is 0.00 the secondary resistance is 2.84. I checked the stator according to Scooter Doc troubleshooting and get zero reading from both the red and black wire and the blue trigger wire. Battery reading 12.8V. Before I go throwing parts at this thing, I would like some ideas/suggestion on where to go next. Any help will greatly appreciated. Thank you, Don B.

[Alleyoop]

zbuck,
You did check for No Spark by either taking out the plug or using another plug and grounded it to the frame or the engine?

Did anything happen before this started? Did you replace something or change something?

Does the Engine turn over but won't catch?
Is your Kill Switch Off.
Do your brake lights come on when you squeeze the brakes.
Alleyoop

[Bashan]

Something is rotten in Denmark. The thing that mystifies me is the zero voltage from both the blue trigger and the red/black power supply. They're two seperate systems, the trigger merrily makes it's little bit of juice as the magnet passes under the pick up coil. The red/black works off of the bigger magneto coil on the stator. Then you get zero resistance on the primary of the coil; how can you get three systems failing at the same time? There has to be a commonality. I think Alley has an idea with the killswitch, they're wired up in a myriad of ways. This one could ground everything out when it's on not run mode. If it's not in that position check the wires and see if something came loose or the switch failed. Also the ignition switch, they can fail and ground everything out depending on how it's wired. Here's an ignition switch testing link. Other than that I'm stumped,; three things at once, what are the chances? Any other ideas out there? Rich

[zbuck]

1st, Thank you both for your replies. Sorry about the delay in replying, had a puter crash. Alleyoop, 1st thing checked was spark to plug, none. It quit on my grandson coming home from work. No changes. Engine turns over fine. Tested kill and igntion switch according to scooter docs-diagnostic spark, both good. Brake lite comes on. With the red/black and blue wiring un-hooked from wiring harness going to CDI, 0.00 both wires. Wiring harness to CDI Hooked back up and wires removed from CDI, 76.1 acv red and black wire, 0.00 blue wire. As stated primary coil 0.00, secondary 2.84 with boot removed. With boot on secondary 0.00. Any more ideas/suggestions will be greatly appreciated. Thank you for your time. Don B.

[Bashan]

The red/black wire from the stator is fine, it should be between 50 to 100v AC. So that shows the magneto coil is working and you've got a good ground on your stator. It also shows your pick up coil is toast. The blue wire should be putting out about .05v AC or a little more to initiate a spark from the CDI. You'll probably have to buy a whole stator assembly, I don't think you can buy just a pick up coil. I think just by a bizarre coincidence you've got a bad coil too, you should get some resistance on the primary. You can't really test it by holding it to ground while cranking the engine because your pick up coil isn't telling the CDI to make a spark. So buy a coil too, they're not that much. Those are my opinions, somebody else can express their erroneous ones . Rich

[zbuck]

Bashan, Thank you for your reply. This scooter has either 19,500 or 9500 miles on it, so I do not think that either the stator or coil/CDI has been changed I ordered the whole package, stator, coil and cdi should have them in a few days. Will reply when installed and let you know what happens. Don B.

[zbuck]

Bashan, This stator is a eight pole dual igntion, 4 wire. could not get any conitnuity (sp) out of one igntion pole all the rest checked fine. Don b.

[Bashan]

You mean the old one? No continuity of course means no circuit = toast. Those wires run around in circles for a reason. Can't carry electrons without an open road.

[zbuck]

Sorry for the confusion, yes I meant the old one. Seeing how it is toast, I am going to tear it apart and see what I can find. Don B.

[zbuck]

Update, installed new stator, getting the same thing as the old one, I have 70 AC volts from red & black wire. 0.00 AC volts from blue & white wire. I am having a hard time believing that both the old & new stators are defective. Could the flywheel be causing this? Magnets are strong and there is ground on the flywheel when checked. Rechecked kill & ignition switches and both checked good. Any more ideas/suggestions will be appreciated. Don B.

[zbuck]

Sorry for the long delay in posting, but I have a small engine business and this time of the year, every body wants there equipment tuned up and maintenance done for the fall and winter (leaves and snow). So had to put the scooter on the back burner. Question on the flywheel/rotor how much air gap/space should I have between the magnet and the pickup coil on the flywheel? Could the magnet on the flywheel/rotor be worn down? Can anyone tell me what the height of the magnet on the flywheel/rotor should be? Thank you for your time. Don B.

[felliott]

The setting should be from .008 to .015. I just checked one that runs and it is .018.

[felliott]

Up date: I just checked a new engine I have on the shelf and it checks .006

[zbuck]

felliott, Thank you for your reply. This scooter has .032 air gap and I see no way of adjusting the pickup coil. Don B.

[Bashan]

I'm perplexed. If you put a new stator in including pick up magnet then it almost has to be in the flywheel. I feel like I'm talking to some of my former professors, who am I to tell them anything? But I thought I'd float a few ideas. You can see the trigger magnet in the flywheel:

See if it's loose or something, hell, maybe it demagnetized. You can test the pick up coil for resistance but you have to use the mount as the ground, from the manual:

The pickup coil should register a value of between 50-170 ohms.

When you guys figure something out let me know. Rich