Scooter not starting

[cyberpunk71]

OK. I am at a lost to what is wrong. I can spray starter fluid in the carb and it will start fine. I bought a bransd new carb and still same problem. I inspected the carb and thought I got a bad carb. Sent it back and got a another new carb and still same problem. It will start up fine on starter fluid. I was getting frustrated so I read the documentation and it said it needed at least 90 octane to run so I dumped the 87 octane and put in 92 octane. Still same problem. I am really getting frustrated.

I checked the compression and its perfect. I have not replaced the spark plug because I have not got one. Fuel flow to the carb is good. When I pump the gas the accelerator pump is pumping fuel into the carb.

The only thing I can think of is the spark plug is not sparking enough to ignite the fuel but its sparking enough to ignite the starter fluid.

I am really at a lost to why this happening. Any help is greatly appreciated.

[rae4180]

try new plug or pull the old out and clean and recap try recap at 06 to 07 mm.

[skuttadawg]

It sounds like a fuel problem since it starts with spray but dies . Check the fuel pecock to see if it is delivering fuel to the carb by unhooking the vacuum line and sucking on it . If unsure which hose is fuel and which is vacuum back trace it or look up a diagram .

I have had water in the gas when I went out in the country and bought gas from an untrusted source . It blew my mind as my scooter was running perfect as good be and the next morning it only started up for 2 seconds and died . First thing I checked to see if the boot was on the plug and it was . Second I pulled the plug , hooked it into the wire , grounded it and hit the start button to see if it fired . Mine did and since yours starts but dies you may not have a sparkplug issue as I did not as well . I called my scooter dealer to tell him about it since it was still newish and warrantied . He told me they had a scooter that would not start up even though everything checked out in troubleshooting . He drained the bowl on the carb and tank then refilled with good gas . Tada is started . I bought a siphon pump at Harbor Freight for 5 bucks to drain the tank since the pecock was under the tank and hard to get to plus I did not want to loosen a line unless I had to . Plus the pump makes it easy to transfer to a gas jug which I used later at a bonfire .

I was first going to say maybe the float valve needs bending as mine did a lil bit as it would overfill the bowl sometimes , but you said you had the same result with a new carb . Can you see fuel flow through the fuel filter ?

Double check for any unhooked , cracked or collapsed fuel or vacuum line . Also double check for leaks at the intake as Glenn had a time figuring out an issue on a customers scooter who left off an O ring has it was not sealed up

Starting spray can be helpful to see if its a fuel issue but the ether in the spray dries out the oils in rubber and plastic parts of the fuel system and not suggesting using it hardly at all .

To better get advice post what engine size you have , how many miles on it , any mods or stock and if it had slowly gotten that way or all of a sudden had starting issues .

On all 4Ts the valves will need to be adjusted at least once , from the PDI for some but many around 2,000 miles or so as mine need adjusting at 2,200 miles . When the valves do not open up enough they do not allow enough fuel into the cylinder to start . Not starting , shutting down once warm and stalling just before coming to a stop are often signs of a valve adjustment is needed

[MEAN_MOTOFINO]

Check For a BLUE spark. Make sure your fuel bowl is filling up. Adjust valves to .004". Make sure timing is correct while your in there. Cant think of much else to tell you at the moment without more information.

[medman1952]

I've not read all the posts but it sounds like fuel is not getting to your carb, when you take it off, is it empty?

I would suspect.

1) vacuum petcok valve (on the bottom of the tank, has at least two hoses on it)
2) fuel filter

The reason it is firing up when you use the starting fluid is that is taking the place of gas that is not getting there, if the spark were weak or absent it wouldn't run even when you use starting fluid.

[MEAN_MOTOFINO]

I do not suspect either of tho since he said his accelerator pump shoots fuel . So fuel MUST be making it into the bowl. The issue is elsewhere. Unless he received two carbs with sticking floats or improperly set (too low)

HOUSE OF SCOOT

[yosemite]

Try this Turn the Fuel Ratio screw clockwise until it stops and then turn it out 2 1/2 turns.
Also another thing that could not be adjust right would be the BUTTERFLY it has to be just a little open to expose the tiny outlet holes for the fuel from the PILOT JET. So after you turn the fuel ratio screw out 2 1/2 turns also hold the throttle just a little open and see if if it start if it starts and dies give the IDLE SPEED SCREW a 1/16 turn Clockwise.
Sam

[medman1952]

Good point, still a air-fuel issue though, not a spark issue I don't think.

Any chance the manifold has a big leak?

[yosemite]

Yes it's a fuel issue if it starts with starter fluid.
Sam

[MEAN_MOTOFINO]

Good point. Check for a cracked manifold or missing gaskets. If it was me and I had this issue reoccurring , I would take the bowl off and make sure the pilot and main jets are clear by either shooting brake cleaner or compressed air through them. Also measure float high while you are in there. Also like said earlier, I would put the idle high until you get it running, then tune it back down to where you want it.

HOUSE OF SCOOT

[cyberpunk71]

Sorry I didn't give more information. This is a Roketa 50cc scooter. The engine is the gy6 type. This pretty much the norm you see on chinese 50cc scooters. There is not a vacuum operated peacock it just comes out to the fuel filter and then the carb. When I got a new carb it came with a new filter and lines. I drained and cleaned the gas tank a couple times thinking something going strange in there. I can remove the hose from the carb and I can drain the whole gas tank in just a few minutes. So I get good flow.

The accelerator pump squirts fuel into throttle body so there is fuel in the bowl.

A leaking intake would cause a very hard to start and rough idle but its not even acting like its igniting fuel. I will check the intake thoroughly when I get home.

[cyberpunk71]

Did a compression test and its 180 psi. That is like brand new. If timing was off I wouldn't get that. If the valve adjustment was off it wouldn't be that good and it would leak down which it doesn't.

[cyberpunk71]

Figured it out. Intake manifold insulator was cracked bad. I'll order one and keep you updated

[cyberpunk71]

Success. Runs good. Thanks for all the help