GY6 157FM By robpatton (Read 5,435 times)

[robpatton]

Have a bunch of questions, I'm just learning.

I Have a GY6157FM motor, very weak spark/no spark no start.

Borrowed a scooter and tested CDI(s) as good, and coil as good.

I assume all thats left is the stator.

From Stator
Ground to:
Blue/White .75vac
Red/Black 112vac
White 6vacish
Yellow 6vacish
Green common to ground


From CDI
Black to coil 13vacish


The status of the White and Yellow shouldn't cause a no spark, should it?

IS the 112vac to high to function?

Am I correct in understanding that the regulator wouldn't effect starting?

I assume its a 6 pole stator. Is there more wires on an 8? Is the flywheel the same from 6 to 8?

Is the flywheel removal tool the same on all GY6 motors?

Thanks

Rob

[tvnacman]

Yellow will not effect spark.
112v is good.
Regulator will not effect if it runs.
Same amount of wires on 6 & 8 pole sdtastors. Different flywheels. The tool is the same.

Now lets get to your problem , check the engine ground , on the the cdi the plug with the two wires pull off the black/white wire and try to start the scooter .

John

[tvnacman]

Oh and welcome to the fourm

John

[sprocket]

Yes 8 pole stators have more wires... at least on my set-up.. many are dedicated to things like the enricher etc.

The two wires that matter to run are the power to the CDI on the red/black and the trigger wire from the pick-up coil usually blue/white

Everything else is battery charge or lights etc...

Look at the red/ black AC voltage from the stator

Attachments:

[robpatton]

My bad, forgot to mention, I pulled the kill wire off the cdi already.

I've also made sure the ground on cdi was common to motor case. Actually added an extra wire to ground to be sure.

The Yellow and White wires I actually checked still plugged in. I think the motor wouldnt turn over with that unplugged. I should double check that.

[sprocket]

Well a weak spark is either CDI or ignition coil or a poor ground or connection somewhere. 112AC is very good by the way.. most don't get it above 90 volts AC

No spark may indicate a bad switch on the brake handle, the side stand is down...or the interlock switch is defective... or the kill switch is shorting the CDI to ground...or the ignition switch is defective...

[robpatton]

Since I've seen a scooter running with my cdi and coil, and I'm being told my stator numbers are ok, I guess we fall back to bad ground somewhere. I've run jumpers thinking I had a bad ground, and I cant manage to make a change.


Checking VAC going from CDI into coil, I get about 16V. That doesnt seem right, does it?

I've got 2 CDIs, I saw both run on a scooter today, but neither changes anything on mine.

[robpatton]

Aug 10, 2011 18:44:14 GMT -6 sprocket said:

Well a weak spark is either CDI or ignition coil or a poor ground or connection somewhere. 112AC is very good by the way.. most don't get it above 90 volts AC

No spark may indicate a bad switch on the brake handle, the side stand is down...or the interlock switch is defective... or the kill switch is shorting the CDI to ground...or the ignition switch is defective...

Am I correct in assuming that if I remove the kill wire from the CDI, that would negate every other safety/etc switch?

Is the 10ohm resistor (which measures as 7for me) able to impact starting at all? What about choke circuit?

[tvnacman]

Have you pulled the plug to check , do you smell gas , let the vac line suck in some gas . pull the plug put your finger over ththe hole amd crank it . Let me know how it. Goes
Johm

[robpatton]

I smell gas, had gas on the plug, and tried it with starter fluid to check, no joy.

[tvnacman]

Unscrew the boot at the end of the coil check the wire be sure of good connection

[robpatton]

I'll go do that, but I had it on a running scooter earlier today, so I feel pretty good about that.

I'm about ready to just build a new wiring harness just to see if its a bad wire somewhere.

I should be able to get by with just 4 or 5 pieces of wire to test it all, I'd think

[robpatton]

Ok, another direction.

is 13VAC at the leads to the coil enuf juice?

[tvnacman]

Im not sure on That . Check for compression . Pull the plug and put your finbger over th he hole and cr az nk

[Bashan]

So the problem with this bike is it won't start or runs poorly? We're kind of all over the ballpark here. You've said you had 16v AC at the coil and then later 13. What is it currently putting out? 16 is normal, 13 is low. Your values on the white and yellow are low but that doesn't matter on the spark. If you're getting 16v AC at the coil and you tested that coil in another bike then I think your good up to the end of the plug cap. Have you tried another plug? If so, I'd have to go with a bad ground/loose connection somewhere down the pike. Have you located and checked the engine ground? Also, it sounds like your pretty good with a multimeter, start checking wires for continuity. That engine is made for a buggy, is it currently in a scooter? Just curious. Rich