(Almost) no spark / engine not runnign

[maglux]

Hi,

hope to get some advice on a technical issue:
 
Agility 50 cc, 4 stroke. 2008 I belive. ~2500 km

Issue:
Scooter always worked fine, but stopped when I was waiting at red last week. Did start again, but didn't run long (10 sec) . Just died /faded away - sounds like ignition problems. Tried again a few hrs later and could drive home (2 min), however almost stopped a few times.

Spark plug has never been replaced (getting a new todday). However afraid it will not be enough.

Have done a few checks:

(1) Gas OK till after the filter (Flows when trying to start, seems like there is a pump "pushing  sequently")
(2) Spark plug a little black, but not bad
(3) plug gets wet when trying to start (some gas reaches the cyl)
(4) no spark when running start engine (only after start engine doesnt run anymore, that is, I see 2-3 sparks after the start engine doesnt pull the engine (it still goes a few rounds around)  So no spark until the start engine doesnt draw from the battery.

Hypotheses:
(A) spark plug worn out ?
(B) CDI / Coil not working properly?
(C) battery needs charging ? (had no problem running the start engine in the start, however got slower)

A and C to be checed today w new plug and recharged battery, any ideas how to check B? Any other advice?

Thanks in advance.

[streido]

Are you not able to crank the engine over and use a meter to check power output is coming from the coil where it leads to the spark plug?

[benhogan73]

I had a similar problem.  Turned out the power lead to the starter was loose and grounding out.   Since that has been tightened down, has not been an issue.

Good luck.

[maglux]

Are you not able to crank the engine over and use a meter to check power output is coming from the coil where it leads to the spark plug?

Can do that and have a meter, could i Ask you to indicte where i find the coil and "how" to meter; what should thenreading be? Tnx

I had a similar problem.  Turned out the power lead to the starter was loose and grounding out.   Since that has been tightened down, has not been an issue.

Good luck.

Interesting, did you also notice that the sparks were not there steadily?

Btw tried with fully charged battery and new plug tonight, no prgress at all...

[blue]

Mine did that after scoot was about a year old I replaced the plug end with a better one then I was all good.

[bmcafee]

Dont know if you have done this yet, I would take off the front panel of the scoot "where the head light is" and you will have access to the ignition and see if all the wires are connected good. I had the same thing happed, that was the cause it looked like the person that soldered it at the factory did a pretty shotty job there was a second wire coming loose aswell. The cover comes off really easy, there are screws on the back and one on the front. you can unplug the the plug for the light so that you can set the panel on the ground while you work. should only take 5 minutes to check. Good luck.

[streido]

You can follow the spark plug wire to find the coil, or take off the plug and get a reading from between the end of the plug wire and earth as you crank it over? Dont know exact voltage but imagine it would be 12-14 volts.

[bmcafee]

streido wouldnt you havet to check it infront of where current gets stepped up I thought that there was ALOT more that 12-14 at the end of the plug.

[streido]

Im not sure, was just throwing ideas out there, you may be right. You can check if you were getting 12v to the coil tho.

[maglux]

So, now I've checked the ignition coil and the pulser coil as described in the service manual. Ohms are all as they should.

Also tried to check the resistance in the CDI, but that was a little more challenging to replicate the values given in the manual - however the manual explicitly states the need to use some measurement devices I don't have -I just tried a normal multimeter.

Furthermore, I've checked that the battry does not drop in voltage when the starter engine is run, hence battery seems fine. Have however been adviced to try with a starter battery from a car, and might do so...

Any other ideas of what to check? Growing anxious it is the CDI, which a dealer quoted me 500 $.... Any ideas how to confirm the CDI is broken?

thanks.

[Kenho21]

$500 for a CDI is about $450 more than I would ever pay..... shouldn't cost you more than $20 or $30 really....

[sidthesloth]

^^^^Agree with kenho, once you determine which type cdi you have, you can look for a replacement. I wouldn't buy a gemuine one, they are the ones that fail.

[streido]

Ebay had race cdi's from china at the start of the year for about £10 plus a couple of £'s delivery, prob about $20-25 at most.

Sure they still have them if you do a search, just be sure it suits a gy6 139qmb 4t cos some the had were 2 stroke only. If you find one email the seller to confirm it will fit your scoot before you order.

Before you do that tho, check your inlet manifold for leaks. Just take out your seat to get at the carb, have a good look at the angled rubber hose the goes from the carb to the engine, prob best to remove it altogether if you cant get a good look in situ. Check where the clamp goes around the hose at the carb for leaks. On mine the clamp had dug into the hose, thro over tightening it, and it had ripped it underneath. Wasnt obvious at 1st but soon as I took the hose out to check it, I saw it right away. Mine would not start up, unless I held the rip closed, would not idle properly, had lost power and was cutting out at lights etc unless I kept reving the throttle.

May not be that but worth looking anyway.

[sidthesloth]

Work out if it is a/c or d/c fired and you will be about right. The next step would be the timing settings.

[Kenho21]

All agilitys use a D/C current CDI to the best of my knowledge