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Post by efeseu on Sept 23, 2015 16:33:52 GMT -5
Ok, so firstly sorry for making posts under posts but yeah...
I don't think its getting any fuel now since I've been trying to start it up a billion times and the spark plug didn't get wet even a tiny bit, meaning that its not getting fuel.
What do I do in this case?
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Post by spaz12 on Sept 23, 2015 18:37:08 GMT -5
What was the results of the compression test?
put some fuel directly in where the spark plug is and try to see what happens. If it starts then you know you have a fuel delivery problem.
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Post by Fox on Sept 23, 2015 22:42:20 GMT -5
Engine spinning fast and no fuel means no compression for sure. Compression loss also means vacuum loss so it won't suck fuel in like it should either.
If the spark plug didn't loosen up, then you have physical damage to the piston or piston related parts. You gotta take off the cylinder head and cylinder and check the cylinder wall for grooves and inspect the piston. You may have lost one of the little clips that holds the piston pin in place. It could be the wrist bearing ha s failed, a broken piston ring or maybe even a holed piston.
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Post by efeseu on Sept 24, 2015 12:23:38 GMT -5
What was the results of the compression test? put some fuel directly in where the spark plug is and try to see what happens. If it starts then you know you have a fuel delivery problem. I didn't check the compression - I don't have anything to do it with... I put fuel in the cylinder + made the spark plug a bit wet but it doesn't start still? Engine spinning fast and no fuel means no compression for sure. Compression loss also means vacuum loss so it won't suck fuel in like it should either. If the spark plug didn't loosen up, then you have physical damage to the piston or piston related parts. You gotta take off the cylinder head and cylinder and check the cylinder wall for grooves and inspect the piston. You may have lost one of the little clips that holds the piston pin in place. It could be the wrist bearing ha s failed, a broken piston ring or maybe even a holed piston. The engine doesn't spin fast now like it did in the video I think my dad's gonna check the carb first on the weekend like he said yesterday and then the cylinder. But if for example a piston ring broke then how does it affect the scooter? Why can't it even start up?
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Post by Fox on Sept 24, 2015 12:54:15 GMT -5
The piston moves up and down inside a cylinder. The rings go around the top of the piston and they are springy so they expand in the cylinder so they are always in contact with the cylinder wall. They are what seal the pressure in the chamber. An engine cannot run with out compression. When the piston moves down it sucks in air and fuel. When it moves up it compresses that fuel/air mixture so it atomizes. (Turns to a fine mist) Then the spark plug ignites the mist. No compression, No start.
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Post by efeseu on Sept 26, 2015 5:44:17 GMT -5
The piston moves up and down inside a cylinder. The rings go around the top of the piston and they are springy so they expand in the cylinder so they are always in contact with the cylinder wall. They are what seal the pressure in the chamber. An engine cannot run with out compression. When the piston moves down it sucks in air and fuel. When it moves up it compresses that fuel/air mixture so it atomizes. (Turns to a fine mist) Then the spark plug ignites the mist. No compression, No start. Thanks. Anyways I'm getting the carb and everything cleaned now. I'll see if this helps...
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Post by derbiman on Sept 26, 2015 9:36:59 GMT -5
Do a leak down test also. It could be the crank seals.
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Post by efeseu on Sept 26, 2015 10:45:13 GMT -5
So carb cleaning didn't help :/ Do a leak down test also. It could be the crank seals. Where about are the seals? I'm going to check the pressure thingy from the fuel tap (pic) once the battery gets charged. The spark plug still isn't wet after trying to start it up a few more times. If this doesn't do anything, then I guess I'll have to take the engine out and see if its the cylinder (oh God...)
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Post by Fox on Sept 26, 2015 12:36:49 GMT -5
Have you verified that you have spark?
My money says you have mechanical damage. The scratching sound was the sound of a dying piston or wrist bearing.
What city you in?
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Post by efeseu on Sept 26, 2015 12:41:06 GMT -5
Have you verified that you have spark? My money says you have mechanical damage. The scratching sound was the sound of a dying piston or wrist bearing. What city you in? Yes, I do have a spark. Now when I sucked in the black tube from the pressure thingy coming from the fuel tap, the fuel moved through although it still didn't start up. I heared like a pop sound now when I tried to start it up. I live in London, UK. South West.
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Post by Fox on Sept 26, 2015 14:08:10 GMT -5
Oh UK huh? I was thinking maybe you lived real close to me or another member that might wanna go and have a look-see at your scooter. Forum member aeroxbud (Paul) lives in the south of England. He's got a 2 stroke. Maybe you and he are close enough that you could get him and the scooter in the same place. You can send him a message here for next time he logs in. 49ccscoot.proboards.com/user/1765
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Post by efeseu on Sept 26, 2015 14:37:25 GMT -5
Oh UK huh? I was thinking maybe you lived real close to me or another member that might wanna go and have a look-see at your scooter. Forum member aeroxbud (Paul) lives in the south of England. He's got a 2 stroke. Maybe you and he are close enough that you could get him and the scooter in the same place. You can send him a message here for next time he logs in. 49ccscoot.proboards.com/user/1765I don't think he lives near me lol Btw. would you think that changing the ignition coil may work ? Maybe its not that good enough anymore ? I think its giving a weak spark.
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Post by Fox on Sept 26, 2015 15:28:10 GMT -5
I think you have low compression due to a mechanical failure. No point in changing the coil until you either do a compression test or take off the cylinder and piston and inspect everything. A compression tester isn't a lot of money. It screws into the spark plug hole. You crank the engine and the gauge tells you how many PSI you have in there. They sell them on Ebay or you can pick one up locally. www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.TRC0.H0.XCompression+tester.TRS0&_nkw=Compression+tester&_sacat=0The "pressure thingy" on the gas tank is called the "automatic petcock". It's a vacuum actuated valve. It shuts off fuel flow to the carburetor when the engine is not running. It's a safety feature that prevents a faulty carb from allowing all the fuel to flow out onto the ground. When you start the engine the vacuum opens the valve but from the video you posted I don't think you have much vacuum due to the way the engine sounded when you cranked the starter so it may not be opening as it should. Sucking on the vacuum line for 10-20 seconds will fill the carburetor with gas but if the compression is low it still won't run. You may hear a pop or two but it won't start. There is a removeable plastic fuel strainer attached to the petcock that protrudes up into the fuel tank. On rare occasions they get clogged up with gunk and the fuel doesn't flow properly but that's not your issue. Just figured you should know everything there is to know about that "thingy"
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Post by efeseu on Sept 26, 2015 15:43:53 GMT -5
I think you have low compression due to a mechanical failure. No point in changing the coil until you either do a compression test or take off the cylinder and piston and inspect everything. A compression tester isn't a lot of money. It screws into the spark plug hole. You crank the engine and the gauge tells you how many PSI you have in there. They sell them on Ebay or you can pick one up locally. www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.TRC0.H0.XCompression+tester.TRS0&_nkw=Compression+tester&_sacat=0The "pressure thingy" on the gas tank is called the "automatic petcock". It's a vacuum actuated valve. It shuts off fuel flow to the carburetor when the engine is not running. It's a safety feature that prevents a faulty carb from allowing all the fuel to flow out onto the ground. When you start the engine the vacuum opens the valve but from the video you posted I don't think you have much vacuum due to the way the engine sounded when you cranked the starter so it may not be opening as it should. Sucking on the vacuum line for 10-20 seconds will fill the carburetor with gas but if the compression is low it still won't run. You may hear a pop or two but it won't start. There is a removeable plastic fuel strainer attached to the petcock that protrudes up into the fuel tank. On rare occasions they get clogged up with gunk and the fuel doesn't flow properly but that's not your issue. Just figured you should know everything there is to know about that "thingy" Thanks. I'll order/buy one tommorrow if I get a chance to and do the compression test. If there is air coming out from the exhaust when I try to start it, doesn't mean that there is compression though?
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Post by Fox on Sept 26, 2015 15:50:08 GMT -5
Yes but it may not be enough. You can have 60-70 psi and still no start. You gotta have at least 100psi, 120+ is excellent.
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