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poor running fs-30s

Old 08-08-2014, 04:44 PM
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Default poor running fs-30s

i have an engine with two gallons on it,has not sounded right from the start.good compression,valve clearence right,(tried from 4 to 14)timing in line with push rod tube,tank height correct,lines ,filters all correct,intake sealing good,runs a 9x6 prop,10% omega,o.s. f plug.(tried several new plugs,tried 5 and 15% also.fuel is good because my old super tigres keep humming on it)the only way to get it to run anyway at all is within 1 or 2 clicks of peak rpm,blows as much fuel out the carb as goes in,have to chase the needle setting through the whole tank,engine will quit while running on the stand idling or revved up if you remove exhaust pressure,no matter rich or lean.please help
Old 08-11-2014, 06:56 AM
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If the engine is blowing a lot of fuel out of the carburetor at medium to high throttle settings, then it's likely that your valves are not properly seating, particularly the intake valve. When running at high throttle settings, no fuel should spill or drip from the carburetor. Something's off there. Without our seeing the engine, we'd really not be able to give a good diagnosis of what the problem might be.
Old 08-11-2014, 08:38 AM
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since my first message,i looked at 2 other 4 strokes i have,they both have a crankcase breather nipple with a regular big hole,this 30 has a pin hole(0.93 millimeters)i switched to a big hole nipple,ran the engine on the stand,and it has so much intake vacumn now,i can run without a pressure line,sounds great.the pressure would build up to the top by the ring gap and eventually stop intake vacumn?what do you think?is this engine suppose to have a needle hole,or is the fitting a defect?thanks,patrick
Old 08-13-2014, 06:41 AM
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Without proper crankcase venting, the engine would run poorly. It sounds like a bad breather port got installed in your engine. Usually, the breather port looks like a fuel fitting with a slightly-larger hole in it. It looks like you found the correct solution.
Old 08-13-2014, 08:18 AM
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thanks for checking my problem.i have warranty but hated to send it in for something stupid.have a good day,patrick

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