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Re: Europa-List: 912S engine vibration

Subject: Re: Europa-List: 912S engine vibration
From: rparigor@suffolk.lib.ny.us
Date: Sat, 5 Aug 2006 19:00:29

Hello Richard

"I am experiencing a slight vibration whilst at cruise speed / rev's."
"Any idea's?"

Have a look at:
http://www.rotaxservice.com/rotax_tips/rotax_vibration.htm
Have a look at causes of vibration and troubleshooting.

You will need to install Microsoft PowerPoint Viewer, free on that link if
Powerpoint will not open as was the case with my version. You need to
download the ppt, then open the viewer, and open the ppt through the
viewer.

Does operating on 1 igniton then the other change things?

You said you adjusted your carb sync. Did you make absolute certain that
the routing of your cables is not creating lost motion due to flexing of
the cables? How about the bug nuts perhaps being overtightened (bug nuts
are the cylinder in the carb linkage arm that you thread the cable through
and tighten the screw to hold the cable) if the cylinder is not able to
rotate free it can cause carbs to become out of sync, just like the
hysteriousis caused by flexing of cables.

You check careful no cable too close to heat and got damaged?

Did you replace the float pins as per the bulletin? If you think carbs are
perhaps a bit rich, turn off your fuel selector in cruise, when bowls go
low mixture will get leaner, best do it only for an instant, turn off
fuel, if it gets better, pull power and turn on selector, go land and
trouble shoot rich. If it has no change, the split second it begins to get
rough, or if you have a EGT and you see going high, pull power, and turn
on selector. I have no first hand experience with a Europa, but the BD5
used to adjust mixture (leaner) by having a needle valve control flow into
the 3 carbs of a Zenoah! It is possable that if you are good with fiddly
things you could actual restrict flow enough with selector to prolong the
good running to be sure.

Did you check to make absolute sure the prop blades are in good shape,
that they are tracking precise and that the angles are exact? The spinner
is tracking true, tight and no severe cracks?

Did you check to see if your undercarriage mounting frame is cracked>
Inspect motor mounts, tight and the motor mount and mounting ring OK.

Are your both your carb float bowl vents in good shape, no kinks and run
to ambient air?

Fly at vibration speed for a while, land and check plugs for color? Best
to pull power quit engine and deadstick but if not wanting to do that,
lose altitude with power setting left alone and lose altitude with steep
turns, and land and shut down as quick as practicable.

Check very careful your exhaust for cracks, your carbs are not covered in
exhaust grunge by chance, are they?

Let us know resolve.
Ron Parigoris



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