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Post by phylowgreen on Apr 21, 2019 18:45:20 GMT -5
Admittedly I'm new to this scooter thing but I'm relatively intelligent and I'm no stranger to YouTube. However, this scooter won't start! I've cleaned and/or replaced nearly every part of the engine. At one point it would start but would die when I gave it gas via the throttle. The Bendix starter part was bad so I replaced it. Now it only cranks. And when I give it gas the cranking slows down. (video at youtu.be/uDWQ7K5d9Yo). It is getting spark. Gas is getting at least TO the carb. Not sure how to check if it's getting IN the carb. Please have mercy on this newbie. Ask me questions, give me advice, share your ideas...I'm determined to conquer this one. youtu.be/uDWQ7K5d9Yo
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Post by FrankenMech on Apr 22, 2019 0:18:59 GMT -5
Opening the throttle increases the amount of air fuel mix that needs to be compressed slowing the cranking speed.
Find a service manual for your scoot or something similar. Then go to the no-start troubleshooting section and follow the sequence EXACTLY. Do not skip any steps!
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Rune 75
Scoot Enthusiast
Posts: 441
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Post by Rune 75 on Apr 22, 2019 4:10:06 GMT -5
Adjust the valves. You'll find guides on youtube.
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Post by aeroxbud on Apr 22, 2019 13:32:48 GMT -5
You said your getting gas to the carb, but not sure if it's getting into the carb. Is the plug getting wet? If not, the carb could be the problem.
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Post by phylowgreen on Apr 23, 2019 17:48:39 GMT -5
Thank you for the ideas and advice. I’ll definitely check out all of that and post my results.
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Post by Lucass2T on Apr 24, 2019 2:13:51 GMT -5
Also try cranking with your hand over de carb inlet to block airflow. Maybe the choke or auto enricher is bad or non working.
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Post by phylowgreen on Apr 26, 2019 17:33:22 GMT -5
Ok so I went with the easy one first and checked to see if it was getting gas. I pulled the plug and stuck my little finger against the hole and cranked. Dry as a bone. I also stuck paper towel in there and cranked. Smelled like gas but also dry. I’m guessing I pull the carb. What do I check for? Btw the carb is new.
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Post by FrankenMech on Apr 26, 2019 23:08:36 GMT -5
Use a service manual. You can also try what Lucass2T said.
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Post by phylowgreen on Apr 28, 2019 9:18:49 GMT -5
Found a service manual! Lots to check. Should determine something. Thank you for the advice.
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Post by GrumpyUnk on Apr 28, 2019 10:08:18 GMT -5
If you remove the carb, check that there is fuel in the float bowl. Alternative is to use the built-in drain for the float bowl. If you loosen the drain, fuel should come out. If no fuel, apply suction to the vacuum petcock to open up the automatic fuel cutoff and fill the float bowl. Re-attach the vacuum line to the intake elbow. Attempt to start. It seems that these carbs do not like to start when 'off idle', i.e., when the throttle is opened past the slow/idle setting. If you disconnect the air tube from the carburetor(leading from the air filter) and operate the twist throttle a couple times, you should see fuel squirt each time from the tube on the lower right of the intake. If you have an accelerator pump, that works, and fuel in the float bowl. And, the flat metal tab on the linkage pushes down on the vertical rod nearby. tom
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Post by phylowgreen on Apr 28, 2019 18:02:42 GMT -5
I loosened the screw on the drain hose and about 2 tablespoons of fuel drained out. Then I saw your post so I’ll go try to start it. ... no start. I don’t see a tube to the lower right of the intake. Also I’m wondering if I have the vacuum hoses hooked up correctly.
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Post by GrumpyUnk on Apr 29, 2019 11:44:39 GMT -5
The tube would be hidden inside the air tube clamped onto the inlet side of the carburetor. You would have to remove the clamp(loosen) and slide the tube off the inlet, and then you should see the tube, angled from about 4:00 o'clock, towards the center of the inlet area. I'd say the diameter is thicker than a wooden pencil lead, actually closer to the diameter of the lead inside the black pencils used in 1st grade when learning to make marks on paper. If you have a vacuum operated petcock, it would mount either to the bottom of the fuel tank, or to a frame rail. The bottom mounted petcock has two lines, one to the filter and thence to the carburetor, the other is a vacuum line routed and connected to the black elbow intake manifold, 'after' the carburetor leading into the intake valve area of the engine. When cranking or running, vacuum pulses will develop, and pull on the diaphragm inside the petcock, opening the fuel valve and allowing fuel to flow through the filter to the carburetor fuel inlet tube, and then to the float bowl. If you have a manual petcock that is operated by rotating a lever, then the vacuum line info does not apply. If you have a 'remote mount' vacuum petcock, it will have an inlet from the fuel tank, an outlet to the float bowl(carb) and one to the intake elbow. If you have other vacuum lines connected to the elbow, they are to operate 'smog' or emissions devices. And, vary by manufacturer and vintage. Many many options apply, and I have yet to see two that are exactly the same. Post a peekshure of your engine, looking rearward, that shows the top of the engine, back towards the fuel line & tank. Maybe something will stand out. tom
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Post by phylowgreen on May 9, 2019 19:22:02 GMT -5
I’ve tried everything suggested but no start. So here’s what I’ve done: * adjusted the valves - .005 on the exhaust and .004 on the intake * put my hand over the intake and cranked. It sucked my hand but no start * pulled the carb and checked the jets. All clear. It’s a new carb but I checked anyway. Gas was in the bowl. * opened the fuel regulating screw, on the outside of the carb, a lot. Now gas squirts out the intake (I have the air box off) no start * checked the fuel petcock. It works All that said the spark plug is still dry. I'm including a pic maybe someone will see something
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Post by tortoise2 on May 9, 2019 20:31:08 GMT -5
I'm including a pic maybe someone will see something Carb bowl vent port should be open to atmosphere, NOT connected to manifold vacuum! Why no cylinder cooling shrouds?
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Post by FrankenMech on May 9, 2019 20:32:45 GMT -5
The airbox must be installed and unmodified, it is part of the fuel mixture regulation. The idle mix screw should be 1.5 - 2.0 turns out from seated for initial start before adjustments. Someone may know about where to set the idle speed screw. I usually set mine to 3-4 turns past contact to hold the throttle open a little before final adjustment. The fuel bowl vent hose goes to atmosphere. It almost looks like your bowl vent goes to a 'T' in the manifold vacuum line which is wrong. The intake manifold vacuum hose goes to the petcock control connection on systems with a fuel tanks above the carb.
The cooling shrouds must be in place if the engine is going to be operated for more than a few seconds. It will start without them but running is a NO NO.
I see Tortoise sees the same things.
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