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Discussion Starter #1
Working on a Homlite trimmer, SX135 with a Walbro wt carb. Has spark, 110psi compression, cleaned carb/new kit. Still will not even fire. Tried starting fluid in carb and plug hole with no luck. What am I overlooking??
Thanks
 

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Is the spark plug getting wet with gas to prove the carb is supplying fuel to the cylinder? Is the spark plug new,since it's possible for a plug to fire until it's under compression? Is the flywheel key sheared and throwing ignition out of sync with compression? Do you have a spark checker hooked up as your trying to start it? I had a Ryobi with a faulty stop switch that drove me crazy.
 

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Discussion Starter #3
No, the plug is not getting wet even when I choke the heck out of it. I have tried a carb kit with no luck. Fuel lines are new and hooked up properly. I am not getting fuel in the bulb though. Seems like it is sucking air. Bulb is new. The rubber nipple under the bulb seems fine. Plug is not new, but I do have spark when I have the plug out and grounded to the engine. I have not removed the flywheel yet. With the plug out I can see the piston is about 1/2-3/4" away from TDC when the magnets pass the coil. Is this about right? I replaced the choke lever for the owner as is was broke due to it being dropped. It ran fine before I returned it to him. Am loosing my patience with this one!!!! :mad::mad::mad:
If it did not have such good compression, I would not be wasting my time.
 

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No, the plug is not getting wet even when I choke the heck out of it. I have tried a carb kit with no luck. Fuel lines are new and hooked up properly. I am not getting fuel in the bulb though. Seems like it is sucking air. Bulb is new. The rubber nipple under the bulb seems fine. Plug is not new, but I do have spark when I have the plug out and grounded to the engine. I have not removed the flywheel yet. With the plug out I can see the piston is about 1/2-3/4" away from TDC when the magnets pass the coil. Is this about right? I replaced the choke lever for the owner as is was broke due to it being dropped. It ran fine before I returned it to him. Am loosing my patience with this one!!!! :mad::mad::mad:
If it did not have such good compression, I would not be wasting my time.
You say it was dropped and broke the choke lever, that much energy probably also broke/cracked the insulator between the carb and block which would create a bad air leak and we know 2-cycles and air leaks don't go well together. Have a good one. Geo
 

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Discussion Starter #5
Yeah, I am thinking something happened as it ran fine prior to returning it to the owner. I will check the insulator. Thanks!!!
 

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Vacuum is just as important as compression.Wonder if the cylinder came loose from the crankcase,OR,is the crankcase cracked some where?Maybe a bad seal on the crank??
 

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Must do vacuum and pressure check. Loss of vacuum and/or pressure will not draw fuel. If you are not getting fuel to purge bulb, the check valve in purge system could be faulty. Usually means fuel lines are not correct.
 
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