fbpx
Jump to Forum..

Engine Vibration

in General Tech Discussion 10 years ago
Hello Everyone, I have a 912 100 hp in a kitfox series 6. My instructor was giving me a pre check ride and we were doing a power off stall when we noticed the engine shaking at 3000 ish RPM. We headed back to the airport and landed alittle fast! Upon getting it back to the hanger we noticed the throttle cable point of attachment ( the 2 nuts back to back) the inside came loose and was not allowing the right carb to idle down. I fixed the loose nuts, I also changed spark plugs since I figured I fouled them. I did a test flight and noticed a vibration again around 3300 rpm. I manually synced the carb and lubricated the throttle carb per Rotax Leaf, but vibration is still there on ground run up! anything over that in RPM is smooth. This is a new engine with 85 hrs on it. Any suggestions??? Any help would be greatly appreciated!

Thanks Patrick!

  • Re: Engine Vibration

    by » 10 years ago

    Hi Patrick

    As it is a new engine and it is happening part throttle I would guess it is your floats.

    Have you checked them carefully? Have you replaced them with the new type?

    This is the first thing I would check as it has happened to us.

    Cheers Mark
    Thank you said by: patrick hintz
      
    Report

  • Re: Engine Vibration

    by » 10 years ago

    Hi Patrick,

    I agree with Mark. Weigh the floats and make sure each pair is less than 7 grams.
    A mechanical sync is just a ballpark starting point. Put a set of gauges on and do a pneumatic sync. New engines can have some cable relaxation or even parts movement within the throttle system and things settle in. Putting the gauges on will also tell you if they are just out of sync or you have a possible obstruction.

    Both of these are just part of a diagnoses to make sure you find your problem.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell

    Thank you said by: patrick hintz, Ole Jonny Sivertsen
      
    Report
You do not have permissions to reply to this topic.
Related Topics
Title Category Replies
Kitfox 3 with 912 1300 hrs on engine 912 / 914 Technical Questions 5
engine preservation (storage) 912 / 914 Technical Questions 1
Engine issue on takeoff. 912 / 914 Technical Questions 16
ROTAX Service Instruction: Introduction of Sodium-Filled Exhaust Valves and New Cylinder Heads for ROTAX® Aircraft Engine Types 912 and 912 i (Series) General Tech Discussion 9
rotax 912 engine resistance to water ingestion 912 / 914 Technical Questions 4

info@rotax-owner.com