Motor starts then dies in 5-10 secs

[bobulator]

Hi all,

I'm a noob here, but had scoots for a few years, and I'm trying to help a friend who has a couple year old zx50, with only 750 miles on it! He's let it sit quite for quite a while, and now can't start it. I figured a clogged main jet, and sure enough it was; cleaned it and it will start fine. Problem it wont stay running more than 5-10 sec. If you try to restart it immediately again, it won't even fire, until you've let it sit 5 minutes or so, then it will again run a few sec at a normal idle then die.

I thought maybe fuel starvation, checked filter, seems OK, and disconnected the line at the carb, started engine, within a few secs fuel started dumping quickly out the line, so I think fuel is getting to the carb OK. When I unscrew the bowl screw, gas comes out, so no problem there. In the 5 sec or so it will idle before dying, if I goose the gas, the engine immediately dies, so I'm guessing there is gas in the carb?

Not sure, Probs with the auto choke? Idle needle or something in that circuit? CDI? Never had one of those so not sure what symptoms they give, however with only 750 mi on the scoot, doubt it is a wearing out issue?

[zombie]

Hey Bro! Try throughly re cleaning the carb. After even a few months varnish builds up INSIDE the atomizers, and TINY passages. There is a product called Chem Dip. Any good auto parts will carry it. It comes in a gallon can. completely disassemble the carb, and put all the METAL parts in a glass container to soak for 24-48 hours. Don't get this stuff on your skin or you will taste it, and smell it for DAYS. Fish the parts out, and wash w/ warm soapy water. I've saved many a carb with this.
There are lots of other possibilities but I think this is the safe bet.
NEW fuel/2 stroke oil/spark plug/fuel, and air filters

[bobulator]

OK, thanks I'll try that. If we get it going, they want to sell it, any idea what a really low mileage ZX50 would go for? He said he paid $2100 a few years ago for it.

[zombie]

In very good shape they RETAIL around 900.00    Trade in is 600.00    These are from Kelly Blue book
It is a discontinued model so dealers will beat you up on it. A private sale is better. I paid 300.00 in near mint for an '05

[zombie]

Pssss They were discon. in 06

[bobulator]

Thanks! I looked at the VIN, it's a 2004, but only has 771 miles on it! Always stored in a garage, so truly like new. I ended up buying it from him for $500.

I took the carb pretty much apart (not completely off the scoot), and took everything out, cleaned extensively with carb cleaner, and reinstalled it. It started right up and stayed running! I took it out for a ride, after warming it up, took it up to about 70 (kmh, not mph!) so I guess it has been derestricted. Parked it and did a few other jobs around the house, then went to restart it maybe 2 hours later, and first it started but died after 10-15 sec, then after that it was like before, would run a few sec before dying, and if immediately restarted wouldn't fire at all. I played with the idle mix screw and idle speed screw a bit, seemed to make some difference, but never got running properly. Finally I just decided to spray some ether into it to get it going, and it started up fine and continued to run, after 5-10 sec I tried to rev it and it bogged, so I let it warm up another 10 sec or so, and then it took off fine and I went for another ride.

I'm really kinda stumped, unless another bit of something got dislodged into the cold start circuit. Does anyone know exactly how it works? Is the tiny tube pulling gas up from the bowl for it? When I sprayed cleaner thru it, it came out one of the holes on the front of the carb!

[zombie]

The auto choke is directly "ported" to the fuel bowl. When cold the choke allows fuel to flow into the vacuum port you sprayed the cleaner thru. When warm that vacuum port is blocked. If you pull the choke out, and mark the position of the plunger you can then jump both leads to any 12 volt battery, and note if it moves the plunger. It could be the problem. They go bad often. Try a NEW spark plug BR8HSA NGK. Clean the air filter. Test the vacuum petcock on the tank by removing the fuel line, and sucking on the vacuum line going to the petcock. Did you replace the old fuel in the tank? Same for the 2t oil. Just a few of the possibilities.
Congrats on the score too. That was a real good deal

[bobulator]

Well I got to work on it today, this time took the carb completely off, removed the choke (the manual calls it a auto bystarter?), cleaned all the pipes and tubes with carb cleaner. Checked the choke, 4.2 ohms, so OK, then applied 12v, and the pin moved out from 20mm to 24mm length, so know it worked fine. Put it all back together and after filling the bowl, it started right away and stayed running! I'm really impressed with the quality of this Kymco, far superior to my first scooter, a Vento Zip 50cc, which I thought was one of the better Chinese clones. Really no comparison in quality. Zombie, thanks for your help!

[Peters]

Nice

Another new ZX owner

We're both new to the club

[zombie]

They are just nice to ride. It dont feel like a scooter