geckofly Posted July 23, 2013 Share Posted July 23, 2013 maintain around 6100 revs on a PA125 for aprox 10 -20 sec and then it surges up to 7200 without any increase in throttle pressure ...any ideas anyone ? it will also drop revs when cruising for a few min at around those values Quote Link to comment Share on other sites More sharing options...
spigot Posted July 23, 2013 Share Posted July 23, 2013 Fuel starvation Cos you've messed with the metering lever Would you like to borrow a pop off gauge while your at it? Sent from my iPhone using PMC Forum mobile app Quote Link to comment Share on other sites More sharing options...
geckofly Posted July 24, 2013 Author Share Posted July 24, 2013 Fuel starvation Cos you've messed with the metering lever Would you like to borrow a pop off gauge while your at it? Sent from my iPhone using PMC Forum mobile app thanks alot for the offer that would be great just have to work out when i could get over could you PM me a contact number? thanks steve Quote Link to comment Share on other sites More sharing options...
gordon_dunn Posted July 24, 2013 Share Posted July 24, 2013 First check the fuel filter inside the carb- i bet it's clogged. When it's clogged it interferes with the fuel flow/ metering system. Also check the pipe that oscillates the membrane - it maybe blocked. 1 Quote Link to comment Share on other sites More sharing options...
geckofly Posted July 24, 2013 Author Share Posted July 24, 2013 First check the fuel filter inside the carb- i bet it's clogged. When it's clogged it interferes with the fuel flow/ metering system. Also check the pipe that oscillates the membrane - it maybe blocked. Thanks for the ideas gorden , but the filter is new and very clean ! and the impuse tube new as well ! Quote Link to comment Share on other sites More sharing options...
notch Posted July 24, 2013 Share Posted July 24, 2013 Also check the torque on your cylinder head bolts, they can come loose and you end up with an air leak at the bottom of the cylinder. Quote Link to comment Share on other sites More sharing options...
geckofly Posted July 24, 2013 Author Share Posted July 24, 2013 Also check the torque on your cylinder head bolts, they can come loose and you end up with an air leak at the bottom of the cylinder. Yes good point and have redone both gaskets and retorqued after every flight ..the amount of attention this motor is receiving at the moment ! girlfriends complaining a bit!! Quote Link to comment Share on other sites More sharing options...
pete_b Posted July 24, 2013 Share Posted July 24, 2013 Could be running rich mid range. Do a plug chop at that rev range if you can. Quote Link to comment Share on other sites More sharing options...
geckofly Posted July 30, 2013 Author Share Posted July 30, 2013 Could be running rich mid range.Do a plug chop at that rev range if you can. Think you were right Pete!, put new metering spring in and seemes to have cured that Quote Link to comment Share on other sites More sharing options...
pete_b Posted July 31, 2013 Share Posted July 31, 2013 Could be running rich mid range.Do a plug chop at that rev range if you can. Think you were right Pete!, put new metering spring in and seemes to have cured that Nice one. Quote Link to comment Share on other sites More sharing options...
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