Hello Scott
"After 15 hrs of great flying my engine has dropped 300 rpm static. and
feels like its missing on a climbing crosswind turn."
Will throw some ideas out:
Check the rubber boots that connect carb to manifold for cracks
Make sure that the position of both carbs are synchronized
Install the new style float pivot pins as per bulletin
Check ignition pick up coil gaps and part numbers as per bulletin and
replace if called for in bulletin
Check your fuel tank vent to outside world
Check Muffler for cracks, leaks, and see if the baffles fell apart
internal
Make sure the fuel bowl vents are going to ambient pressure or air-cleaner
intake pressure and not restricting flow
Make sure you have proper heat range spark plugs, and proper gaps, and you
are using Whacker silicone based thermal conductive compound torqued as
per bulletin
Very important, make sure you do not have a restriction in fuel system,
kinked hose, or a nipple that has too small a ID (I was sent different
nipples, some had a very small ID that was pretty restricting)
Still bent on restriction, do you have a factory fuel system? Not a Andair
Mini Gasculator in there by chance? If you do take it out and give a try.
Make sure restrictor for return flow not clogged, you did install a return
flow line?
If you try drinking through a straw with a pin hole in it, you know air is
a lot easier to suck up than the drink. Fuel system is no different, look
for leaks that are letting in air. Roger bull said he had sight T on
intake side of fuel system, and could get air sucking through the sight
when fuel was a bit low causing the plane to play Silent Night. a small
leak will cause your symptoms.
You have the proper size main jets? Are your jet needles set correct? Are
your carb diaphragms leaking> Do you have bulletin jet needle needle aux
hold downs installed?
Do you have any sort of special stuff in your fuel system that can be
skunking you? Like fuel flow transducer? Fuel pressure gauge sender that
is leaking in air?
Does it run same on both mags? is there excessive drop during mag check?
Did you try running off reserve? Does aux fuel pump help?
Is the routing of fuel lines insulated near hot under the cowl?
Check to see if you have any vacuum leaks, make sure cross tube hoses are
in good shape.
Give a try pitching nose up on ground and doing a static check? (I am just
shooting from hip, put on 3 car ramps, and pull tail way down and tie it
down??)
Is there a restriction between carbs and fresh air? Are the airfilters
restricting? Did you follow precise airfilter instructions?
Again fuel restriction, when your aeroplane is on car ramps with tail low,
run a fuel flow test in that configuration, do it for a while, like 10
gallons worth.
Check your ignition wiring:
http://www.greenskyadventures.com/engineservice/TechTips/912Ignition/912IgnDiagrahm.htm
Good luck
Ron Parigoris
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