Wont' start?

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I was happy when I started to take the spark plug out and it was loose I could do it with my fingers, but, after checking the gap, putting it in tight didn't make it start any better.
Still, the engine on the 50cc motorscooter has started many times now, but it never runs more than 30 or 45 seconds.
It starts even if no ether is used, often fairly quickly (5-8 seconds with the electric starter), if it's been 10 minutes or more since the last time I ran it or tried to run it.
But after 15 seconds it dies.
It runs pretty fast if I give it a lot of throttle, but it still starts to die within 15 seconds. Sometimes if I had it running fast, it lopes along very slowly for another 10 seconds, instead of dying more quickly. If I try to start it immediately after it's died, I don't think it's ever started then.
Removing the gas cap didn't help (it wasn't on tight in the first place because I have no key and have to use a screwdriver if I put it on tight. And I'm sure it's not air-tight even when perfect.)
It couldn't be bad gas or it wouldn't start at all.
I've removed the spark plug and the gap turned oout to be good, 0.7mm, and it sparks every time, when I electric crank it with the plug out of the engine.
The owner's manual talks about not starting but not about starting and dying. I'll go look at the manual
I think it's a fuel problem. It's certainly not compression and I'm 99% sure it's not spark.
I think it's starved for gas.
Parts that come to mind are the electric choke, the idle screw, a bad fuel-pump-like-device, or some obstruction in the fuel line.
The shop manual says adjusting the idle won't make much difference, and come to think of it, it dies when the throttle is far above idle.
It starts so there must be enough choke then. How long would a miniscooter take to fully warm and fully open the choke? A lot more than 30 seconds, right? but to partially open? 15 seconds? Maybe the choke never opens at all??? And that's why it dies. Then 10 minutes later the engine is totally cold again?
I tried to take off the fuel line to see how much comes out, but I didn't have the right tool. And now it's dark out. Tomorrow should be warm too.
I have to read about the fuel-pump-like-device.
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Micky wrote:

You need to put back the 2" hose with the end cut at an angle .
--
Snag



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Micky,
Does it die if you continue giving it squirts of ether?
Dave M.
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On Thu, 26 Nov 2015 18:00:00 -0500, "David L. Martel"

I can't keep squirting because I need to keep my left hand on the left brake, and the air intake is just 8" offf the ground near the rear axle, on the left side. If I kept my right hand on the right brake, that would be even harder.
Now if I kept my right hand on the left brake.... no, my back will be towards the scooter.
Maybe I'll get a friend to help.
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wrote:

Maybe you need to investigate that hose a little better. ;-)
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On Thu, 26 Nov 2015 18:24:55 -0500, snipped-for-privacy@aol.com wrote:

The mystery hose. I put in my pocket, went out, and lost it. Unless it's in some other pants. Probably not.
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On 11/26/2015 03:15 PM, Micky wrote:

Fuel pump like device? I've only got a fuel pump on one bike and that's because it's fuel injected. For the others the fuel system is stricktly gravity fed. otoh my father refused to let me buy a Vespa when I was 16 since he thought any two wheeled vehicle with little bitty wheels was a death trap. I've followed his advice although some of the new scooters are sort of cute. Or at least the little red head I see on a pink scooter every now and then.
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wrote:

I'd read about in the manual but my memory could be better. Reading again this evening, it's not a pump or even pump-like, but it is, what did I call it in the other posts, a vacuum-controlled control valve.
How does that work? Vacuum at the base of the carburetor, where the vacuum hose goes, turns the gas on or off?

Better than a pink head on a red scooter. If you have nothing that isn't faster or slower than her scooter, maybe you could lie down on the pavement as she approaches and look injured.
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wrote:

intelligent answer without knowing what you are working on. Or even if it's worth futzing with.
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On 11/26/2015 4:15 PM, Micky wrote:

Almost certainly a fuel DELIVERY problem. I occasionally (which is why I haven't torn it down or taken it to the shop to have it done) have a very similar problem with a ZTR mower with a 22HP engine. Will start right up then, within 15-20 seconds, will die off and won't start again. Replaced the filter, then the fuel pump, all to no avail.
Finally, before calling for help, I pulled the fuel line from the output of the fuel pump to the carb and tried blowing into it. No luck but I wasn't sure if it was plugged or if I merely lacked the lung power to get the job done<g>
Grabbed a 60cc syringe with a catheter tip that fit nicely into the fuel line and tried blowing INTO the carb. Again, no luck. Changed tactics and tried sucking OUT from the carb and it worked. After doing so I could pump into or suck out of the carb. Something in there blocking or stuck. Reattached the fuel line to the pump, turned the key and I was in business. Didn't have that problem for at least five or six weeks - after a spell of temperature swings and little use. This time my first step was to try and draw fuel from the carburetor and again I was successful on the first try.
Give it a whirl; what do you have to lose?
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On Thu, 26 Nov 2015 19:04:46 -0600, Unquestionably Confused

I'll give it a try.
I also went out in the dark and looked again for the fuel filter. It wasn't in the tank, I'm glad to say, but it was hidden by a frame member so I didn't see it. Only a little bigger than the last section of my thumb.
So I'll try that too.
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On 11/26/2015 10:28 PM, Micky wrote:

Some of those inline filters can lurk in the strangest places. Are you getting clean gas out of the tank? A little rust can clog the filter in short order.
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It's milky brown, but is that rust or too much water in the gas? http://www.lcbamarketing.com/phase_separation_in_ethanol_blen.htm Phase Separation in Ethanol Blended Gasoline’s

I used the turkey baster almost the first thing, well before I posted, but I was only able to get 3 or 4 tablessppons out. Then I rolled up newspaper and stuck that in the tank. That gets the liquid but I don't think it gets solids if any like the turkey baster would if it could. I tried the newspaper thing about 20 times, 10 pieces, 2 ends each. At first I let it sit 2 or 3 minutes and it went 3 inches up the paper, but I changed to 10 minutes and 6 inches up the paper, and when I was all done, the gas level seemed about the same!!

As to rust, I've the impression that the tank is plastic. Maybe not. I'll check.
Also http://www.postandcourier.com/article/20110501/PC1602/305019925 Ethanol isn't a problem for automobiles because they are used almost daily. It's an entirely different matter for boats, which often sit unused for months at a time and have vented fuel systems that allow moisture to enter the tanks. -- [I think this thing has a sealed tank, but it might have sat for months unridden.]
"The biggest problem is ethanol is alcohol-based and alcohol absorbs moisture from the atmosphere," Murphy explained. "Over a period of months, it can add up to a half-gallon, maybe as much as a gallon of water."
That water separates from the gas and sinks to the bottom of the fuel tank. When a boat takes off, the bow rises and the fuel rushes to the lowest spot in the tank, which is where the pickup tube is located. Water is sucked into the engine, causing it to misfire.
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On Thu, 26 Nov 2015 19:04:46 -0600, Unquestionably Confused

OKay, I tried that today.

I once blew hard to blow something up and I felt one of Eustachian tubes swell in my head, or at least that's what it felt like. Scared me, the thought of it bursting in my head. So I don't blow that hard anymore.

Okay, I didn't have 60 but I found a 20cc syringe, still in its sealed, sterile, paper wrapper. I've had it in my junkbox for maybe 20 years, don't remember where I got it. This was the day I was saving it for!!

Well it was too small, but it had an opening-cover that was bigger so I cut the tip off of that and put the hose on it.

No luck.

Pulling slowly did nothing, so I quickly pulled the plunger straight out of the rest of it. After 3 or 4 times, I saw a trace of something in the hose. Did it 10 more times and the trace got longer, eventually a bit of gas was coming out almost an inch, and then receding again.

So I was psyched, and when I started the scooter right afterwards, it seemed to run faster (with more throttle) and a longer, but it was only a few seconds longer at most and then it loped and then it stalled.
Debated whether to drain the tank and buy a gallon of hi-test, and then it started to rain, earlier than predicted. It's going to be colder or rainy for a week.
The milky brown gas is probably water in the gas. Maybe the top layer is gasoline and it floats, but after 30 seconds it uses that and the rest comes from the bottom of the tank which has more water, then after 10 munutes somehow there is gasoline in the bowl t hat floats to the top of the bowl and it works again. Makes no sense.
But I think I have to drain the tank, remove the carb and turn it upsided down to pour everything out.
Unless there's some way I could empty the bowl without removing the carb? Blowing air through it from a little compressor? How long would that take?
(One poster said he couldn't take the carb apart without drilling out the rivets.)
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On 11/29/2015 01:20 AM, Micky wrote:

A lot of motorcycle carbs have a screw to drain the float bowl. I'm not a big believer in snake oil but I've had good luck with Sea Foam for cleaning up carbs without disassembling them as long as the engine runs enough to pull it through.
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wrote:

Well, at 15 seconds a pop, how many times do I have to run it to use the same amount that is in the bowl? And how many times do I have to run it to actually flush out the bowl? I know, the second question is much harder to answer.
Still I'm not sure how hard it is to take off the carb so the sea foam might be worth it. I think there is a drain screw but I dont' think I can get at it without removing the carb. I know that's not the carb designer's plan but it's worked out that way. I can't feel it or see it or see it with a dental mirror. I can only see it when I look at what I think is the same carb in Amazon
(Amazon.com product link shortened) The top picture enlarged. Clearly shows the screw. Don't be confused by the grey hose, which is actually behind the screw, and just happens to be in that position, not connected to anything. I guess they include a llittle piece of hose, as well as a fuel filter. The whole carb is upside down in this picture.
The bottom picture, enlarged shows the strange short tube, which comes from somewhere much higher. In this picture, the bottom of the carb is on the bottom of the screen and the output is in the middle of the screen.
But it will probably have to wait until the spring.
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On 11/29/2015 03:14 PM, Micky wrote:


https://www.youtube.com/watch?v=SCcdaTjuIL4

I don't know if you've found that video and if it's the same carb but it looks like the sort of armored tube is the drain and there is a screw at the bottom of it?
Couple of relevant comments but no real answers. Electric choke?
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wrote:

I'll look next. ....., Wow, an excellent video for me Thanks a lot.
I had tried to open the air cleaner cover but even in the daytime, the sky was too cloudy and dark to find the last screw. Should have gotten a flashlight, but it's soft plastic and I pulled it open enough to pull out the foam air cleaner a little bit. Looked like new and clean. And I left it pulled out a bit so no interference with air intake for a few tries.
I'm 99.9% sure this carb has no drain *hose*, but it almost surely has that drain, so maybe I won't have to open the carb, maybe I just have to clean it out.
It's also a good video becaus it lists eveyrthing I have to do to get the carb off.
IS IT A BAD IDEA TO REMOVE THE CARB, LEAVE THE INTAKE MANIFOLD OPEN, EXCEPT FOR A RAG STUFFED IN IT, and the hoses open because they're not connected, FOR THE REST OF THE WINTER, UNTIL APRIL? Maybe I think I can do everything in one day and then I can't and it drags on to April. Why does cold weather seem like it would hurt the inside of the engine more than warm weather, when chemical reactions are faster when it's warm?
When I lived in Brooklyn NY 30 years ago, there was always one weekend day each month in the winter warm enough to put the top down and go for a drive. Now I have 7 days to work with but I don't remember always getting warm days in the winter in Baltimore. It's not that I can't work in the cool or cold -- I can and do when it's important -- but that this is meant to be fun, and it's not so much fun if I'm cold. And I'm not going to ride it, for fun, unless the weather is warm.
As to reassembly, after I had already decided to check the petcock by sucking on it, I read a review that seemed to say it was part of assembly instructions to suck on it, though other reviews said there were no assembly instructions!! I think there really are.

Yes, it has that. I can imagine the choke causing problems. I wanted to look at it, or control it manaually. It's attached with two Phillips screws I felt I wasn't getting a good bite on one screw and the full-size screwdriver I had with me wouldn't fit the other. I meant to come back with a smaller one. And I was trying to figure out how not to lose the washers that someone said it had.
OTOH, I can't imagine it getting that warm in 15 seconds that would cause too much choke to be a problem. And if too much choke were the problem, I can't imagine it running 15 whole seconds. There isn't much change in choke position in beteen the 3rd second and the 15th second in my experience with cars.
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On 11/29/2015 11:28 PM, Micky wrote:

You should be okay. I've used a piece of duct tape over engine openings I wanted to cover too. A little acetone takes the goo off if there is any when you remove it.
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On Thursday, November 26, 2015 at 4:15:12 PM UTC-6, Micky wrote:

Sounds like fuel starvation, look for a clogged fuel line. Blow it out with compressed air.

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