HELP!! Problematic no-start condition!

[erictheviking666]

Okay I have not been able to get my Scooter too start since LAST Monday. I had just replaced the carb about 2 weeks prior too this and it was running better than it had since I first got it. So I rode it too work last Monday and everything was fine. I came out at lunchtime to run down and get something to eat and it would not start. You could hear it just about to catch and start but it wouldn't quite do it.

I could see fuel going to the carb and originally assumed I had just flooded it out or something, so I let it sit until I got off at midnight. I went out after work and still no-start, so I had too leave it at work and drive the car a couple of days untill I could get the Scoot home.

Once I got it home I checked the plug and it looked a little rough so I went and got a new one, but still had the same condition. I can see fuel coming from the tank too the carb and I loosened the carb drain screw and fuel pours out. So I am assuming it has enough fuel too run (Am I right here?). Going by normal diagnostic procedures I checked my valves (I had just set them 2 weeks ago) but they were spot on. The motor feels and sounds like it still has good compression, but I don't have a tester and haven't pulled a reading yet.

So I checked the spark plug and I have fire. I tried cranking with the foam air filter in or out (thinking maybe it was plugged up) but still the same condition. I even squirted some starting fluid up into the air intake tube and still will not start. So I'm thinking maybe it has spark but it's a WEAK spark, so I tried a spare coil I had but still the same issue. So I'm back to a possible weak spark?!? I guess I need some help in testing my Stator to verify if I have a good spark? Anybody out there know what kind of readings I should be getting out of the stator when I try too crank it? Anybody have any other ideas on something I may have missed? Also even though there's fuel in the fuel bowl on the carb is it possible it's still not getting into the combustion chamber when I'm trying to start it?

Any help would be appreciated as I am about at my wits end with this one.

[2strokd]

Had one just like that the other day..Hers some from the posts.

Yeah, i tried starting fluid and it wouldnt even sputter, backfire, nothin. As a last ditch effort before pulling the motor i tried another carb and it fired right up! Weird that it wouldnt even fire with s/fluid? Thanks for the reply!
Im not to fond of these stock CV style carbs..This is the third GY6 scooter ive worked on with bad carbs that no kinda cleaning will fix. One had a crack that caused idle/air whackyness.
Another just wouldnt stop leaking nomatter what i did or switched around on it. Seems like one outta 5 maybe is ok? Maybe thats why i see em on ebay for $30 new and a discount if ya buy more than 10 lol! Why would ya need 10 carbs! LMAO!
Im happy tho! It puts a buck or ten in me pocket! All get off my soapbox, sorry!
Brent, you ever try a different carb on yours? I was thinking of trying my Mikuni VM18 on my
GY6 50 wanna these days to see if it helps

[shiftless]

If you have spark, fuel and good compression..... I'm thinkin carb too

[Fox]

It's fairly common for brand new carbs to have metal shavings or other debris inside them from the machining process that will get lodged in an air passage or a jet after some time. If a good thorough carb cleaning doesn't help, then my next suspect would be the valves and then the CDI, Coil etc...

Try squirting a little fuel straight down the carb throat and see what happens. If you get a short run and then it dies then it's a carb issue most likely but check the valves again anyway.

That's my 2 cents anyway...

[90GTVert]

Mar 30, 2010 12:48:06 GMT -5 erictheviking666 said:

I can see fuel coming from the tank too the carb and I loosened the carb drain screw and fuel pours out. So I am assuming it has enough fuel too run (Am I right here?).

It should have enough fuel. If the float is set too low it usually will either not draw in any fuel or it will run and die when you hit the gas or after a couple seconds on the gas. It wouldn't hurt to verify that the float height is correct. I don't think that's gonna be the issue, but it isn't too hard to do. Look around in there and make sure nothing is clogged or no debris is lying around.

Mar 30, 2010 12:48:06 GMT -5 erictheviking666 said:

Also even though there's fuel in the fuel bowl on the carb is it possible it's still not getting into the combustion chamber when I'm trying to start it?

That is possible. Like jmstar said, you could have a clogged passage or jet. I cleaned a customer's carb thoroughly and 2 weeks later he came back with the thing only running 7MPH. It had a clogged main jet that quick after a carb cleaning. I replaced his lines and filter after that. The point being, it doesn't take much to clog a little main jet or pilot jet or the tiny passages in there. I've got a Tecumseh carb from a snowblower sitting in my garage now. I cleaned it, cleaned it again, and finally got a rebuild kit and took the caps off to get all the passages, new gaskets, new screws, etc... Stupid thing gets fuel to the bowl and still won't pick it up to send it to the engine.

[erictheviking666]

Thanks guys, I'm leaning toward the carb to. I think I'm gonna try some starting fluid in the combustion chamber tomorrow. If it fires up and runs a few seconds I'm gonna take that carb off and clean it out throughly again.