Those are static compression test results of approx. 139 psi. You are usually better off doing a differential leak down test. The test pressure can be 80-87 psi and the usual residual is usually 83-85.(5.7 - 5.8 bar)It will tell you a little more. You can tell if it is a bad valve on the intake or exhaust and bad rings.
Roger Lee LSRM-A & Rotax Instructor & Rotax IRC Tucson, AZ Ryan Airfield (KRYN) 520-349-7056 Cell
The fuel inlet chamber I mention is the area between the fuel line inlet on the external part of the carb from were the actual fuel line attaches to the carb, to the top of the float needle valve seat area inside the carb. In our case it was a tough one to find. It was actually a flake of yellow marker paint used on the fuel distribution block of a certified 912F on a Diamond Katana with stainless fuel lines. They use this yellow marker paint on that particular aircraft to identify if the banjo bolt ever comes loose. Someone had at one time removed this banjo bolt and in doing so allowed a flake of the yellow marker paint to get into one carbs fuel line!
Have you found the problem yet? Have you done a comparison check of your ignition systems? I'm having a problem with one of mine. It drops off about 600 rpm on one while the other one only drops about 100 rpm. My ground rpm with both systems has dropped about 300 rpm at full power. I'm still hunting for my problem. At least I know its electrical.
Hello verybody who did try to help me out with this problem.
We finely found the problem or actualy not we but the service center in Germany.
We checked every thing and ended up with dismanteling the engine and send it to Germany.
They found there that the main cranshaft bearings were worn out. Which made the engine not comming to his max ref's.
We bought a brand new engine and are waiting for the final results. and hope that Rotax comes up with a financial solution. This is because the engine has only 550 hours on its clock and has had its normal maintenance.
Keep you all informed when we hear anything from Rotax
it is possible that the fork which lifts the fuel shut off valve in the carb is bent leading to only one float lifting whilst the other jams slightly against the inner part of the carb.A random mixture problem will then occur altered by fuel flow and engine shake. It is very easy to bend this fork when replacing the float bowl. The clue will be that the lift pin on one of the floats is not as polished as the other or the polish mark is very near yhe end of the lift pin.From experience this fault has made it look like there is carb icing and the engine runs rough then may be all right when the float lift pin does move over and eventually lift the fork. In flight it has caused us to believe we had icing. having fixed it there is no problem now.
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