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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 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 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 bjg on Apr 12, 2013 12:03:02 GMT -5
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Post by bjg on Apr 11, 2013 13:47:33 GMT -5
Hi everyone,
I pulled the carb off my scooter a few days ago and cleaned it (It's a horizontal 250cc btw). While I had the carb off I inspected the rubber inlet flange that connects the carb to the engine and found a spacer between the motor and the flange. The flange itself has a metal surface with a rubber oring that seals to the spacer and the spacer also has a rubber oring that seals to the engine. Though i have seen the spacer for sale online I can't find this spacer listed in any of the 250cc manuals I have and I'm wondering if this is normal or if the previous owner of my scooter put it on to try and stop an air leak. Any thoughts?
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