Hi Dave,
Thanks for your suggestion. All seems to be OK with the pipes and hoses,
but I found a small slither of silicone in one of the needle jets, which I
hope will solve the problem.
Best wishes,
William
----- Original Message -----
From: <DJA727@aol.com>
Subject: Re: Europa-List: 912 Engine Problem - Request for help
>
> In a message dated 7/24/2003 11:34:15 PM Pacific Standard Time,
> combined.merchants@virgin.net writes:
>
> > Has anyone experienced a similar problem and can anyone help with
> > suggestions please?
> > On recent flights I have experienced some irregular misfiring when
> > descending with about quarter throttle and also the occasional hiccup in
cruise, but
> > on my last flight the engine was running so roughly in the cruise I
aborted
> > the flight and nursed it back home.
> > I carried out some tests on the way back. It ran very smoothly on full
> > throttle, it ran very smoothly on closed throttle, but in between it ran
very
> > roughly. I checked the ignition when running roughly, but there was no
change
> > on either mag. I tried coarsening and fining the prop to see if it was
rpm
> > related, but it wasn't. I changed to reserve tank, but no change. The
carbs
> > are well balanced at tickover and the engine runs smoothly right down to
1500
> > rpm. The fuel filters are clean. I can only assume that the problem is
> > related to carburation, but find it difficult to believe that one can
have a
> > partial blockage, or too much fuel with a needle jet in its mid range
only. As
> > tickover is smooth and roughness stops in flight when descending with
closed
> > throttle, I can only assume that the slow running mixture adjustment and
> > associated jet are OK. Are there any other jets apart from the main
needle and
> > slow running jet to consider? Although I never have a problem with !
> > starting, can a problem with the starting carb affect the mid range
running
> > only? Can a faulty float valve affect mid range only? My engine has
done
> > about 480 hrs, should I be considering renewing any of the carb parts as
a
> > precaution / planned maintenance etc? I have had a brief chat with
Conrad, but
> > he was unable to put his finger on the problem, so presumably my
symptoms are
> > unusual. He suggested I should check the needles for wear and the carb
> > rubber mounts / sleeves for splits, which I will.
>
> Check your little hoses that run around the carburetor area. I have a 914,
so
> I don't know if the system is the same, but I had a very similar problem
and
> it turned out to be a split in one of those hoses.
>
> Dave
>
>
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