fuel line By shaunb24 (Read 894 times)

[shaunb24]

Today my scooter wanted to stop running for its own reasons.
I looked at the fuel filter and the fuel is just trickling into it. what can I do to fix this?

[alleyoop]

It could be that your valves need to be adjusted, if they are tight they will stay open a little and will cause low compression very low suction to operate the Vacuum parts on the scoot.

OTHER POSSIBLITIES:
Is this a Gravity Fed system(GAS TANK ABOVE THE CARB) Petcock Vacuum Valve, Or GAS TANK BELOW THE CARB a FUEL VACUUM PUMP?

If the latter check your vacuum hose for any leaks, also air leaks around the carb area, cracked Intake Manifold, Loose Clamps holding the carb etc.

To check take the hose off the CARB and out it in a container and crank the motor over, FUEL SHOULD stream out, if it doesn't try taking the gas cap off the tank and crank it again and see if it then streams out.

If still no then take the VACUUM hose off going to the VACUUM operated pump BY THE CARB and suck on it. If fuel still does not flow out then the pump is bad or the fuel hoses are clogged.
Alleyoop

[shaunb24]

The gas tank is above the carb and I was checking it some more and took the line the fuel comes out of the petcock off and no fuel came out at all.

[shaunb24]

Okay I got a new update with a little help I took the fuel line off of the petcock and turned the scooter on and it a lot of fuel out. So I checked the vacuum lines and found one to be damaged so I fixed it and it seems to have made it better but still not where I need it. It should not be a vacuum line issue if it lets fuel out when the main fuel line to the carb is taken off right? Or could it be a problem with my main fuel line?not sure what way to go here.

[alleyoop]

Here is how it works:
The Vacuum line attached to the PETCOCK OPENS the VALVE when there is SUCTION and allows fuel to flow to the CARB. Suction is created when you crank the motor and OPENS THE VALVE inside the PETCOCK and FUEL WILL COME OUT. WHEN you stop cranking the motor the VALVE SHUTS off and NO FUEL WILL FLOW.

So if fuel flows when you crank it and STOPS when you stop cranking the PETCOCK is good and the VACUUM is GOOD.

So what is the problem NOW?
Alleyoop

[shaunb24]

When the main fuel line is attached to the petcock the fuel will flow vary little to non at all even when reeving the engine. When the line is not attached it flows fine.

[cruiser]

Once the fuel line is connected to the carb, the fuel flow should only be a trickle with the engine running. To put this in perspective, let's say your scoot gets about 75 mpg. It would take 90 minutes of traveling at about 50 mph to see one gallon of gas going through the fuel filter. When the engine is idling, it uses even less fuel so it should be just trickling.

[shaunb24]

It is a trickle but its not enough to really keep the engine going when you accelerate.

[scott]

Sounds like your carburetor needs cleaned or replaced. It may not be allowing the proper fuel flow from the line.

It is much easier and recommended to just replace it because they are inexpensive and also because, you can never remove all of the shellac buildup without ultrasonic cleaning and that will probably cost more than a new carb. you should also replace the diaphragm when cleaning because they eventually become deformed from ethanol and other fuel additives.

If you decide to clean it this video may help


There are many stock carbs out there. Some are better than others and a few are unserviceable junk.

Assuming you have a stock 'GY6' engine, here are links to a couple that have worked very well for us in these situations with no adjustments needed other than idle setting (these are serviceable and adjustable if needed).

50cc
.partsforscooters.com/Carburetor_qmb139" rel="nofollow" target="_blank">.partsforscooters.com/Carburetor_qmb139

125/150cc
.partsforscooters.com/125-150cc-GY6-Carburetor-169-49" rel="nofollow" target="_blank">.partsforscooters.com/125-150cc-GY6-Carburetor-169-49

[JR]

You could be right on the carb Scott and we have the Big Guy's carb cleaning 101 here too:

thescooterprofessor.proboards.com/index.cgi?board=genvideo&action=display&thread=356

Big Guy is a member here and a very good friend of mine. We also have some other good carb cleaning videos in the video tech section;

thescooterprofessor.proboards.com/index.cgi?board=carbvid50&action=display&thread=357

Agree with you on the carbs some good some junk and IMO if a good cleaning doesn't do the trick I generally recommend buying a new one versus buying even a diaphragm.

From the way you talk you must have a shop or work on scooters and if so we welcome another helping hand wrencher on the forum and even if you don't work on them in a shop, welcome to the forum.



JR

[alleyoop]

Need little more detail on HOW the motor is acting. From you say it starts fine and stays running.
So what happens when you go to ride it is the important thing.

When you give it gas does it BOG, BACKFIRE makes a BURP or POP sound?

The sound a motor makes will tell you what is needed so listen to the sound the motor makes when you twist the throttle SLOWLY as well a FAST turn on the throttle.
Alleyoop

[cruiser]

You could be having carb problems as noted above. Have you checked the fuel flow through the filter with the line disconnected at the carb? If the flow trickles, then the filter may be plugged.