Today's Message Index:
----------------------
1. 02:54 AM - O-320 Sputtering on One Magneto (George Nielsen)
2. 05:50 AM - Re: O-320 Sputtering on One Magneto (Stuart Hutchison)
3. 08:00 PM - Re: O-320 Sputtering on One Magneto (FLYaDIVE)
Message 1
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| Subject: | O-320 Sputtering on One Magneto |
Yesterday I test ran my O-320. When taking it up to 1800 rpm it
sputtered on one magneto but ran well on the other.
Thereupon I set the engine to 1000 rpm and ran on the magneto which
caused sputtering. I slowly raised the speed to 1800 rpm and the engine
ran well. I tried the other magneto and then both and it continued to
run well. There was little difference in speed between one magneto and
another, and the difference with one magneto and both was about 150 rpm.
Thereupon I shut the engine down.
After that someone reminded me about the method of running the engine
and leaning out to remove deposits and prevent sputtering. After almost
half an hour I restarted the engine, ran up to 1800 rpm on both magnetos
and gently leaned out until the engine started to run erratically. I
then tested the magnetos with rich mixture and the drop was within
around 150 rpm with little difference between each magneto.
Does anyone know which is the better method of the two to clear spark
plugs, or whether there is a still better method? Thank you.
When switching off both magnetos for a moment while the engine was
running at around 1000 rpm I got a bang. Is that because of backfiring
or dieseling? Is such a procedure recommended? I know that one gets
backfiring if one switches off the engine with the magnetos and not by
leaning out.
George Nielsen
RV-6 PH-XGN
The Hague, the Netherlands
Message 2
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| Subject: | Re: O-320 Sputtering on One Magneto |
Gday George,
A common problem. As distinct from in-flight leaning (which can have serious consequences
if not properly managed), on the ground you can pull the idle power
mixture way back (straight after start) until the engine just about stops then
richen slightly. There isnt enough fuel to lead foul the plugs, nor enough
fuel to cause high EGTs, so you really cant hurt the engine on the ground by
leaning that far with very low power/load. If you attempt to takeoff with the
mixture that lean, then the engine simply doesnt have enough fuel to respond
and its plainly obvious! Conversely, doing this by halves may leave you short
of power on takeoff if you forget to select full rich, so do this very positively
or not at all.
If you do get plug fouling, method 2 - running the engine up to 1800-2000 rpm slightly
leaned with BOTH magnetos selected (to burn all the fuel and generate
heat in the cylinder) is the preferred way here in Australia.
The bang is normal and like any backfire momentarily turn the spark off while
the fuel / air is still flowing and you can cause an explosion in the exhaust
pipes (i.e. outside the cylinders) when the spark is re-energised. Yes, you should
do this quickly before shutdown to ensure neither of the magnetos are live
with the ignition switch off. The longer you leave the magnetos off the more
chance you have of a backfire . this need only be very momentary. Remember
that the magnetos are self-sustaining after start and that the ignition switch
is designed to ground the magneto to stop the spark so if either of the P-leads
are broken, the switch is unable to ground the magneto and the engine would
remain live even with the switch in the off position.
Cheers, Stu
On 28 Sep 2014, at 7:52 pm, George Nielsen <genie@swissmail.org> wrote:
>
> Yesterday I test ran my O-320. When taking it up to 1800 rpm it sputtered on
one magneto but ran well on the other.
>
> Thereupon I set the engine to 1000 rpm and ran on the magneto which caused sputtering.
I slowly raised the speed to 1800 rpm and the engine ran well. I tried
the other magneto and then both and it continued to run well. There was little
difference in speed between one magneto and another, and the difference with
one magneto and both was about 150 rpm. Thereupon I shut the engine down.
>
> After that someone reminded me about the method of running the engine and leaning
out to remove deposits and prevent sputtering. After almost half an hour
I restarted the engine, ran up to 1800 rpm on both magnetos and gently leaned
out until the engine started to run erratically. I then tested the magnetos with
rich mixture and the drop was within around 150 rpm with little difference
between each magneto.
>
> Does anyone know which is the better method of the two to clear spark plugs,
or whether there is a still better method? Thank you.
>
> When switching off both magnetos for a moment while the engine was running at
around 1000 rpm I got a bang. Is that because of backfiring or dieseling? Is
such a procedure recommended? I know that one gets backfiring if one switches
off the engine with the magnetos and not by leaning out.
>
> George Nielsen
> RV-6 PH-XGN
> The Hague, the Netherlands
>
>
>
>
Message 3
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| Subject: | Re: O-320 Sputtering on One Magneto |
George:
The procedure to do a Mag Check is:
~1800 RPM
~Left Mag - observe RPM
~Both - observe RPM
~Right Mag - observe RPM
Now, I also do a Mag check at 1500 RPM. Why? Because as RPM increases so
does the output of the Mag. So, at a lower RPM if there is a problem you
should easily find it.
Neither of your two written Plug Clearing Procedures are correct. The
procedure to clear fouled plugs is:
~HOLD YOUR BREAKS - DO NOT USE THE PARKING BRAKE - HOLD YOUR BRAKES...
Long story - It is a safety reason.
~Slowly [Don't go ridiculously slow.] increase the RPM to MAX STATIC RPM.
Around 2200 to 2300 RPM.
~ LEAN - Lean until rough and richen just a little, VERY LITTLE.
~Hold the RPM and Lean for about 20 seconds
~Slowly decrease the RPM back to 1000 RPM. Let it run here for 1 minute.
~Then do a Mag Check (see above). If you still have a fouled plug REPEAT
the procedure for fouled plugs. Repeat three (3) times if necessary. If
you have done the procedure correctly for the three (3) times and still
have fouled plugs - - - Remove and Inspect the Plugs.
Barry
"Chop'd Liver"
On Sun, Sep 28, 2014 at 5:52 AM, George Nielsen <genie@swissmail.org> wrote:
> genie@swissmail.org>
>
> Yesterday I test ran my O-320. When taking it up to 1800 rpm it sputtered
> on one magneto but ran well on the other.
>
> Thereupon I set the engine to 1000 rpm and ran on the magneto which caused
> sputtering. I slowly raised the speed to 1800 rpm and the engine ran well.
> I tried the other magneto and then both and it continued to run well. There
> was little difference in speed between one magneto and another, and the
> difference with one magneto and both was about 150 rpm. Thereupon I shut
> the engine down.
>
> After that someone reminded me about the method of running the engine and
> leaning out to remove deposits and prevent sputtering. After almost half an
> hour I restarted the engine, ran up to 1800 rpm on both magnetos and gently
> leaned out until the engine started to run erratically. I then tested the
> magnetos with rich mixture and the drop was within around 150 rpm with
> little difference between each magneto.
>
> Does anyone know which is the better method of the two to clear spark
> plugs, or whether there is a still better method? Thank you.
>
> When switching off both magnetos for a moment while the engine was running
> at around 1000 rpm I got a bang. Is that because of backfiring or
> dieseling? Is such a procedure recommended? I know that one gets backfiring
> if one switches off the engine with the magnetos and not by leaning out.
>
> George Nielsen
> RV-6 PH-XGN
> The Hague, the Netherlands
>
>
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