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Post by pr on May 3, 2019 7:36:54 GMT -5
I have a 49cc 2 stroke Chinese-type scooter, sold here in France under the brand name "Ride". I don't know the engine type, and I can't find the engine number but the registration document lists the type as L1ERDEC, if that is relevant. It is a 2015 model, but only done 40km from new! Until recently it ran OK on the few times it was used, but now it starts, will idle for 30 seconds or so, then stops. The vacuum fuel cock works fine and I have stripped, checked and cleaned the carb. I suspected the float valve, but this is also OK, and in any case when it stops there is still fuel in the float chamber. It has a solenoid operated choke which may not be working correctly and could be related to the problem. When connected to 12V the solenoid doesn't pull in, and if it is disconnected when the engine is running it carries on idling and doesn't stop as before, but cuts out as soon as the throttle is opened. Presumably the solenoid is connected to a temperature sensor which should remove voltage and allow the choke needle to return to the closed position when the engine warms up. Does anyone out there have any ideas? The local dealer who supplied the bike is totally unhelpful, though can sell me a new choke solenoid for about 50 Euros, but before I do this I would like to know if anyone else has had a similar problem?
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Post by snaker on May 3, 2019 10:15:32 GMT -5
First off I am familiar with the US stuff, I don't know if your's is the same or a different animal. I'll help if I can.
Carbs: Your experience working on small carbs is a big factor. Have you worked with them much? The reason I ask is because time after time people "clean the carb" by spraying a bit of cleaner and calling it done. Any thing less than a through disassembled scrub is suspect. I have quite a bit of experience and many times I have fixed a plugged carb not by the first cleaning, but by the second, because I missed something. Also these things are made so one brand/model carb is completely different than another. Clean it again.
Choke: Its actually a enricher (choke restricts air, enricher adds fuel). Normally referred to as the Auto-choke. There is no sort of sensor input. The Auto-choke receives a electric as long as the engine is running. It is spring loaded full open and slowly closes and holds close as long as the engine runs. That slow close is supposed to coordinate with the engine warming up.
Your diagnostic seems to me to be a carb regular circuit problem and what your seeing is maybe the Auto-choke's losing attempt to compensate.
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Rune 75
Scoot Enthusiast
Posts: 441
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Post by Rune 75 on May 3, 2019 10:23:43 GMT -5
The auto choke is provided with 12v all the time when engine is running. There is a small heating element in the choke that heats up gradually after the engine starts running. This causes a small wax reservoir in the choke to expand and push the small piston and needle further out and close off the choke circuit in the carburetor. This will take about 3-5 minutes depending on the outside temperature. If you want to test your auto choke, hook it up to 12v and see if it slowly expands out.
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Post by pr on May 4, 2019 6:42:11 GMT -5
Thanks for your comments guys. I have stripped and cleaned the carb at least twice.....washed in clean petrol, blown dry, and all the jets and drillings I can find cleaned out gently with a stiff plastic bristle (Wife not pleased about the state of her hair brush now!),so I'm fairly sure it is clean. I have connected the auto choke to 12V and it doesn't seem to move, but I will try again and leave it longer. I didn't realise it had a wax theremostat and assumed that it was a solenoid which lifted the enrichment needle when energised, ie when the ignition is switched on, and gradually closed as the engine warms up. So, I was expecting it to pull in as soon as it was powered up. I'll have another look at it and report back!
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Rune 75
Scoot Enthusiast
Posts: 441
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Post by Rune 75 on May 4, 2019 7:00:42 GMT -5
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Post by oldgeek on May 4, 2019 10:07:49 GMT -5
Did you use a pencil to push the needle jet from the carb body? That is often overlooked when cleaning a carb. There is usually plenty of garbage stuck in there.
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Post by pr on May 7, 2019 11:05:59 GMT -5
Hello again
Yes the float needle has been removed and cleaned....no crud in there....the bike has only done 40km! We bought it for my wife to use but shortly afterwards she broke her wrist and now doesn't have enough strength to operate the front brake lever. I'm fairly sure the problem relates to lack of use, as it was fine until laid up for 6 months last year. The carb had some old fuel residue, but all has now been cleaned out and it has a tank of nice fresh fuel. I removed the auto choke and connected it directly to 12v as suggested, and it does extend about 3mm after 5 minutes or so, however, when re-connected to the 2-pin plug on the loom, it does not extend when the ignition is on. The supply side of this plug shows no voltage with the ignition on, and when the engine is started, it shows 0.4v cold, reducing to 0.14v as it warms up.....doesn't sound right to me! Where does the supply voltage routed from? I can't find a fuse box or terminal box, but it seems there is a high-res joint somewhere. Unfortunately I don't have a wiring diagram so tracing it is a problem. I was looking for a fuel fault, but it now looks as if there may also be an electrical fault as well.
The symptoms are.....auto choke fitted and connected, it starts, idles for a couple of minutes then slows and stops - no difference hot or cold. Sounds like fuel starvation, but if the float chamber is removed immediately it is full to the correct level. Auto choke disconnected, after warming up a bit it starts and continues to run indefinitely at a fast idle, but cuts out as soon as the throttle is opened a bit.
So...a bit of a mystery!
Peter
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Post by pr on May 19, 2019 7:00:54 GMT -5
Hi again....I guess this is a bit of a mystery to everyone else too? Does anyone know if I can download a wiring diagram?
Peter
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Post by geoffh on May 19, 2019 8:48:36 GMT -5
Peter,some pictures of your carb will help,read up in the tec section and clean the carb again every little orifice needs to be clear,check the enricher on the bench,a new one should be under £10 the engine needs to be complete with the air filter on to run,many scoots suffer from air leaks swamping the delicate balance of air/fuel required,keep at we will help.
Geoff
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Post by oldgeek on May 19, 2019 10:31:45 GMT -5
Hello again Yes the float needle has been removed and cleaned....no crud in there....the bike has only done 40km! We bought it for my wife to use but shortly afterwards she broke her wrist and now doesn't have enough strength to operate the front brake lever. I'm fairly sure the problem relates to lack of use, as it was fine until laid up for 6 months last year. The carb had some old fuel residue, but all has now been cleaned out and it has a tank of nice fresh fuel. I removed the auto choke and connected it directly to 12v as suggested, and it does extend about 3mm after 5 minutes or so, however, when re-connected to the 2-pin plug on the loom, it does not extend when the ignition is on. The supply side of this plug shows no voltage with the ignition on, and when the engine is started, it shows 0.4v cold, reducing to 0.14v as it warms up.....doesn't sound right to me! Where does the supply voltage routed from? I can't find a fuse box or terminal box, but it seems there is a high-res joint somewhere. Unfortunately I don't have a wiring diagram so tracing it is a problem. I was looking for a fuel fault, but it now looks as if there may also be an electrical fault as well. The symptoms are.....auto choke fitted and connected, it starts, idles for a couple of minutes then slows and stops - no difference hot or cold. Sounds like fuel starvation, but if the float chamber is removed immediately it is full to the correct level. Auto choke disconnected, after warming up a bit it starts and continues to run indefinitely at a fast idle, but cuts out as soon as the throttle is opened a bit. So...a bit of a mystery! Peter The voltage for the choke comes directly from a stator winding, so the motor has to be running for the choke to close. wiring harnesses can be a PITA. You could wire in a toggle switch and 12 volts directly to the choke, or switch it directly from the key would be better. A temporary connection to 12 volts should tell you if the choke is your only problem. Remember it may take a few moments of riding to clear out the excess fuel and oil the improperly operating choke may have been letting in. If you still have issues, I would clean the carb again. I previously mentioned about pushing the jet tube the needle rides in out of the carb to make sure it is clean. Just to be clear it is seperate from the needle. Good Luck. |
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