little or no spark - questions about ignition coil

[Mrfixit66]

Hello Everyone: I have a Chinese 50cc engine with a number of D1E41QMB stamped on the motor. The actual engine is stampled “Dingoi” on the side cowling, and the name etched into the plastic body side panels is “Sun Ray”. The ignition coil that I have on the scooter is identical to an Ignition Coil for Qingqi QM50QT-B2 50cc 2-stroke scooter (See picture below).
Currently, I have a very weak spark and believe that the ignition coil is the culprit. When I measure the primary terminals of the coil with an ohm meter, I get infinity on the 200 ohm range. When I move the multimeter to the 20K range, I get 536 ohms, when the positive lead of the ohms meter is on the laminations post and the negative lead is on the male spade connector. However, when I reverse the ohm meter leads to the same connections, I get infinite resistance. This indicates to me that the coil seems to have a diode in the primary winding. The secondary coil resistance is 14.k ohms when I place the negative or positive lead of the ohm meter on the laminations post and place the other lead on the sparkplug wire. Once again, if I move the positive lead on the male spade connector post and negative lead on the sparkplug, I get infinite ohms.
So if anyone can assist me in the following questions:
1. Is the ignition coil that I have a special coil (Ignition Coil for Qingqi QM50QT-B2 50cc 2-stroke scooters) with an internal diode built into it? Do all coils have this internal diode built into the coil pack?
2. Can I use any ignition coil that is listed as a 50cc Chinese moped ignition coil? I know that I might have to address the physical mounting issues, but electrically speaking will any coil work?
3. I notice that some ignition coils have a green marking on one of the spade connectors. Does this mean anything?
4. I have notice that some ignition coils have the lamination connection go thru the body of the coil. Can I use one of them and only mount the coil pack using one side of the lamination pack?

[Big Bill Gilesbie]

ill tell you this you did alot talking for nothing if its broke get a new one it doesnt have to be bike specific as long as it has a ground and kill wire you can use a 1pe40qmb ignition coil and if it still has weak spark i would check your stator until you see a nice bright strong spark you can also try cleaning up stator and just double check all connection are debri free i think your on the right track

[sledgebeast]

I am having this same exact issue!
Engraved # on the back of the Gearcase near the brake says
1E41QMB... I do not see a D but many search results show a D
as in D1E41QMB...

So did you figure out what was causing this spark issue.

I have looked extensively and do not find a CDI on this model.

Mine is a Sinski Ventura. Occasionaly I get a spark for a few
revolutions and then it disappears.

Was it your Stator?

I can not get the Magneto/Flywheel off it has an odd size thread.
Did you get your mag off? If so what thread size was it?

Any info you have would be appreciated.

ty

[Mrfixit66]

As it turned out, my coil wasn't bad after all. I changed the spark plug and cleaned out all the connections and fully charged the battery. I did discover that my piston was scored pretty bad. Hence, I tore the engine apart and replaced the piston and rings. Afterwards, it started right up and has been running great over a year. I think the lack of spark may have been due to the fact that the crankshaft wasn't able to turn around fast enough due to the bad piston. Good luck

[sledgebeast]

Yea first thing I tried was a new coil. Does the same thing.
You can see my piston thru the exhaust port and its clean.
My Batt spins her over very fast and some of the time I get
a barrage of sparks then it completely goes away. Which I
find weird cause if it were the Stator you wouldn't expect it to
come and go. Mine does not appear to have anything like a
CDI Box anywhere on the Bike. Did yours have anything like
a CDI or Ign Module. The only thing I have found is a Starter
Relay. NO other boxes except a VR up front under the cowling.

O BTW main thing I needed to find out since you had your engine
apart you must have removed the Magneto/Flywheel. & its an
odd size tool thread. Not the common one that fits GY6 and the like.
What size thread tool did you use to get it off? Was it 28mmx1.5mm RHT ???

[sledgebeast]

If you have the Specific tool for that and it has any markings on it
that would be a great help to me. It is really hard to find anyone who
has worked on this motor much less disassembled it like you have...

ty

[sledgebeast]

Tried a new Coil. Both will give spark for a few revolutions then quit sparking.
Sometimes it will Return and spark again for half a dozen to a dozen revolutions
then just quits again. Other times I can't get either coil to do that at all.

I also traced down the Black w/ W.Stripe. Where those 3 come together under the
frame I severed the one that goes to the Kill Switch/Key Just in case the Ign Key
Switch is Bad. No Change. The only thing Left is the Stator. I also used Automotive
Jumper Cable to Make damn sure the frame & Block were Grounded. No change!
I also tested that Kill Lead from the Ign Switch with a Multimeter for Continuity.
I have confirmed when turned to off that lead becomes Grounded. The Ignition
Key turned to Run it becomes Open as Expected. So that's not the problem either.
However I have finally removed the Magneto. I can confirm that a D1E41QMB
Magneto/Flywheel requires a 27mm Thread x 1.5mm Pitch Right Hand Thread Puller.
Which is not in any of the 10 piece kits. On another forum I posted this info also
and suggested its hard to find. I will say Near Impossible. I got by with a
27mm x 1.25mm pitch puller you will get no more than ~ 3 threads deep before
it binds up but with a little luck I was able to Pop the Mag. Yes I cheated!
I have gone back and scoured the Web and have found it seems Nobody Make that
size puller. A person might go to Diamond Screw Products and get a 27mm1.5mm
Bolt and drill out the center and tap it for a Push Bolt & ground a point on it. But Geeze
Qinqi/Geely WTF!!!!! Using a completely unsupported Thread size for the Puller Hole!
Stupid Chinese!

BTW I did solve my spark issue.
Once I removed the Magneto I could see the Stator winding for the spark
has a visible burnt hole in the fabric covered winding. Ordered a Stator!