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Post by bjg on May 17, 2013 9:13:04 GMT -5
So I've been having trouble starting my scooter and I originally thought it was an air/fuel issue so I changed the carb and I have the exact same symptoms. The carb bowl has gas (and I have a new filter installed), starter is cranking strong, i have good compression, but scoot wont start.
As a test to confirm the fuel issue I took a small amount of gas an put it in through the spark plug hole, reinstalled the spark plug and cranked it and it still wont start. Now I'm thinking maybe its the spark. I checked this previously and I see a spark on the plug and it seems strong enough but looking at it again I'm not sure it's firing enough.
When I crank the starter with the plug out and up against the case the spark appears about every 1.5 to 2 seconds. My question is should it be firing more frequent than that? The tach shows about 180rpm during starting so I would think I'd hit top dead center more often than that.
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Post by JR on May 17, 2013 11:35:54 GMT -5
Seems a little long between spark plug firing.
What is the scooter doing, does it run?
Have you checked the compression?
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Post by scootnwinn on May 17, 2013 11:51:57 GMT -5
What kind of plug is it? Just replace it they cost like $2
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Post by bjg on May 17, 2013 12:29:19 GMT -5
Compression is good and I did change the plug but I cant get it to run at all. The plug is an NGK DR8EA and I replaced it just a few months ago. I suppose it could be bad. I was thinking it should fire more frequently as well. The spark seems reasonably bright, could it be a CDI issue or do you think this is more of a plug type problem?
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Post by alleyoop on May 17, 2013 12:46:37 GMT -5
Did anything happen before this started, did you drop the scoot or did you do anything.
As your watching the spark plug firing it should almost look like a continuous spark. If you can count 1thousand 2thousand before a spark that is not right.
If so it could be your CDI or PICK UP coil. Did you by chance do anything like taking off the flywheel and or anything around that side.
Alleyoop
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Post by carasdad on May 17, 2013 12:54:30 GMT -5
DX Even at the normal cranking speed...plug fire should almost look as a continuous pulse of spark..almost too rapid to differentiate one spark from the next. Many things can cause intermittent spark..so check as alleyoop posted. However! even with intermittent spark you should get a few 'pops' here or there..and often a few bursts of them in succession.
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Post by scootnwinn on May 17, 2013 12:57:09 GMT -5
Check your grounding both the engine and ignition components... and all the stuff they said up there...
Also make sure the plug wire is making good contact on both sides and is tight
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Post by bjg on May 17, 2013 13:31:00 GMT -5
Well....not exactly. Last fall as it got colder it got harder and harder to start. I cleaned the carb over the winter and found that the air/fuel screw was missing an oring. I don't know if it was an issue or not but I didn't think I could find just the little oring and the whole carb was pretty cheap so I replaced it. The new carb has the air fuel screw at 1 1/2 turns and the idle screw is set so the throttle plate is just cracked open a little bit. I made sure the bowl fills with gas (and it isn't coming out of the overflow) and went to start and it cranks but wont start. When i checked the plug after cranking it a bunch the plug was not wet but did smell of gas. I checked compression and I'm over 100psi so I took a bit of fuel line, dipped it in the gas and trapped a bit of gas and put that directly in through the sparkplug hole and tried cranking it again. If it were a fuel air issue it should have started and run for a minute or two with that much gas in the cylinder. It didn't start so I started looking at the spark itself and there is definately more than a second between sparks when I'm cranking it.
I have some experience with small engines but I'm no expert. The tach I have is inductive and it wraps around the plug wire. If it's showing 180rpm when i'm cranking then, being a 4 stroke, I would think that means I should see 45 sparks per minute or roughly 1 a second (please tell me if i'm wrong). I'm gonna say I'm much closer to 2 seconds than 1 second. Trouble is that I don't know what it should look like normally.
I'm open to suggestions on what to check if anyone has any. I still had the original plug and I tried that but it made no difference. I suppose both could be bad so I'll pick up another new one today. Beyond that I'm not sure where to go with this.
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Post by alleyoop on May 17, 2013 14:04:41 GMT -5
Here is how it should spark:
Alleyoop
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Post by bjg on May 17, 2013 14:15:46 GMT -5
Mine is definately not that fast. Is that a 2 stroke or a 4 stroke? I'll try and post what mine is doing when I get home.
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Post by alleyoop on May 17, 2013 14:38:27 GMT -5
Does not matter 2 stroke or 4 stroke.
Alleyoop
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Post by bjg on May 17, 2013 14:42:59 GMT -5
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Post by bjg on May 22, 2013 12:18:16 GMT -5
I updated the link in the post above. I'd really like to know if this is normal for a 4 cycle. I know alleyoop said it didn't but that doesn't make sense. If I understand it right a 2 cycle fires on every rotation of the crank and 4 cycle is every other rotation.
Anyway, if you folks could look at this I'd appreciate it. Thanks.
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Post by alleyoop on May 22, 2013 12:54:38 GMT -5
Post the VIDEO ON HERE, where you have it requires to download some more stuff on our computer(NOT GOOD).
Alleyoop
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Post by bjg on May 22, 2013 13:55:11 GMT -5
I would if i could. I've been using mediafire to to put files on the web and it works well for images but I can't seem to get video to do anything other than link the download.
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..BAD TO THE BONE..
