Many thanks, John,
I try to keep my coolant temp up to about 90deg.C by partial blanking of the
rads. However, I have found a small slither of silicone in one of the
needle jets, which might have been the cause.
Best wishes,
William
----- Original Message -----
From: "Europa Aircraft" <europa@gate.net>
Subject: RE: Europa-List: 912 Engine Problem - Request for help
>
> William,
>
> Check your CHT temps. If they are too low, the engine can fowl, even on
> unleaded fuel. I had exactly the same problem, however when I got the
> engine to run a little hotter, it went away. The roughness didn't show up
> until the engine had about 400 hrs.
>
> Good Luck!
>
> John Hurst
> Europa Aircraft
> Lakeland, FL
>
> -----Original Message-----
> From: owner-europa-list-server@matronics.com
> [mailto:owner-europa-list-server@matronics.com]On Behalf Of William
> Mills
> To: europa-list@matronics.com
> Subject: Europa-List: 912 Engine Problem - Request for help
>
>
> <combined.merchants@virgin.net>
>
> Hi All,
> 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.
> Many thanks for any help,
> Regards,
> William
>
>
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