TNG 50cc Won't Start On its Own, or Stay Running By ajacks504 (Read 1,061 times)

[ajacks504]

First post!

I'm working on a 2005 TNG Venice right now and having some issues.

Symptoms:
The scooter will not start, turns over, but will never catch.
If I spray carb cleaner in it, and open the throttle almost all of the way, it can get it to start, then it will run somewhat rough, until it runs out of carb cleaner, then it dies.

What we have done:
Replace the old gas, flush the fuel lines.
Verified that gas makes it to the carb. If I pull the fuel line, and turn the engine over, fuel flows free. So, I've got vacuum, I think.
Pulled the plug, cap, stuck a nail in it, and watched it arc over to the plug's cap (didn't have the right socket to remove it). The spark looked very weak, but it was jumping 2 gaps, possibly a problem.
Removed carb, cleaned and inspected. It wasn't really dirty, and everything looked ok, but admittedly didn't give it great a good look over.
Adjusted the jet, all the way in, out almost all of the way, trying at various rotations... nothing.

I think this is where we are:
- Exhaust system isn't clogged, shouldn't be the issue.
- Fuel delivery to carb is good, pulls vacuum.
- At least getting some spark, enough to start carb cleaner.
- Air isn't the problem, won't run with the air box off.

I'm worried that possibly the float might have a pinhole in it, and never letting any gas in there.

What should we try next?

Thanks for your suggestions!

[JR]

The later is a possibility and you meant a pin hole in the diaphragm. Also the didn't go through it thoroughly is not good especially with old gas? Jets can be clogged and since it will run with throttle wide open this is a good possibility. Low speed jet clogged no start up.

Got to open it up and do a very good cleaning and look hard for a pin hole in the rubber diaphragm.

Keep us up to date and Welcome to the forum!

JR

[ajacks504]

Thanks JR.

Maybe I mis-spoke. I can get it to run from cab cleaner only, if i start it with the throttle wide open. It runs, then dies once its burned all the cleaner.

So, it appears, that under no circumstances can I get it to run off of gas provided by the carb.

I think a better clean is in order...

[alleyoop]

Yes your pilot jet and or passage are clogged.
Take the carb bowl off and clean out the jets and then spray into the jets holes in the carb to clean out the passages. When you spray into the holes the jets screw into make sure the spray comes out from it outlets. The outlets are tiny so they can get clogged and varnish up if if sitting for months without gas flowing out of them.
Alleyoop

[ccortus]

If your problem still exists after you clean the carb really good, I would suggest checking out your CDI. My old scooter was having similar problems and replacing that fixed it. I'm not sure how to test a CDI (I just threw money at my scooter and it worked that time) but it's worth checking out.