Today's Message Index:
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1. 04:14 PM - CJ starting/mag drop issues (Jay McIntyre)
2. 05:24 PM - Re: CJ starting/mag drop issues (Frank Stelwagon)
Message 1
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| Subject: | CJ starting/mag drop issues |
Hi all.
Had a CJ through for an annual recently and we noticed a couple of
irregularities which we have not been able to rectify as yet...
1) #1 mag exhibits a constant mag drop throughout all RPM ranges of about
100 RPM and nearly stops at idle.
Initially we focussed on the mag drop as although not alot, something was
not quite right. We changed the plugs for new items (no effect); retimed
the mag (no effect); changed the coil (no effect); and somewhat grasping at
straws, changed the mags from side to side.
This seemed to fix the fault and the owner took the aircraft away but the
fault seems to have returned. Any ideas out there? We are thinking it must
be a plug lead. I know many of you have experienced plug lead woes in the
past but in 15 years of operating CJ's in a dry environment I have never
had a problem before. (aircraft has standard factory harness and leads but
is operated in a wetter environment than I am used to).
2) Aircraft can be hard to start. Intitally we thought this was related to
the mag problem but it seems to be more fuel related. Initally after the
annual I could not get it started and thought it was the part-worn set of
plugs we had just installed. I swapped them out for the old plugs with no
effect and then realised the aircraft had been parked on a slope for some
hours with minimal fuel in it... turned the aircraft 180 degrees and sure
enough she started first go.... a-ha - must have been no fuel to carb I
thought....
Alas no.... still exhibits hard starting from time to time.... will turn
and turn with no sign of life and then exhibit quite a violent ignition
event on one or two cylinders. Sometimes it seems it is over-primed (lots
of fuel out of the manifold drain) but other times under-primed. Other
times it will start happily and repeatedly. Engine being cold or at
operating temp does not seem to matter.
As seen above mag timing has been checked. Additionally we have checked
shower of sparks (OK) and primer line (OK) but are a bit lost as to where
to go now. Next step might be to pull the primer atomiser from the blower
case and check it is not blocked/damaged.
Perhaps the two symptoms are related - perhaps not?
Any ideas/help on this gratefully accepted!
Regards, Jay
New Zealand
Message 2
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| Subject: | Re: CJ starting/mag drop issues |
1. Go with the auto plug conversion!! The original plug leads are old
and not great to begin with.
2. Remove the primer line at the engine fitting, put it in a container
and work the primer. Saw a CJ with a cracked line on the suction side
of the primer, made a great air pump but no fuel. Had the same starting
problems.
Frank
CJ6-A
----- Original Message -----
From: Jay McIntyre
To: yak list
Sent: Saturday, April 06, 2013 4:11 PM
Subject: Yak-List: CJ starting/mag drop issues
Hi all.
Had a CJ through for an annual recently and we noticed a couple of
irregularities which we have not been able to rectify as yet...
1) #1 mag exhibits a constant mag drop throughout all RPM ranges of
about 100 RPM and nearly stops at idle.
Initially we focussed on the mag drop as although not alot, something
was not quite right. We changed the plugs for new items (no effect);
retimed the mag (no effect); changed the coil (no effect); and somewhat
grasping at straws, changed the mags from side to side.
This seemed to fix the fault and the owner took the aircraft away but
the fault seems to have returned. Any ideas out there? We are thinking
it must be a plug lead. I know many of you have experienced plug lead
woes in the past but in 15 years of operating CJ's in a dry environment
I have never had a problem before. (aircraft has standard factory
harness and leads but is operated in a wetter environment than I am used
to).
2) Aircraft can be hard to start. Intitally we thought this was
related to the mag problem but it seems to be more fuel related.
Initally after the annual I could not get it started and thought it was
the part-worn set of plugs we had just installed. I swapped them out for
the old plugs with no effect and then realised the aircraft had been
parked on a slope for some hours with minimal fuel in it... turned the
aircraft 180 degrees and sure enough she started first go.... a-ha -
must have been no fuel to carb I thought....
Alas no.... still exhibits hard starting from time to time.... will
turn and turn with no sign of life and then exhibit quite a violent
ignition event on one or two cylinders. Sometimes it seems it is
over-primed (lots of fuel out of the manifold drain) but other times
under-primed. Other times it will start happily and repeatedly. Engine
being cold or at operating temp does not seem to matter.
As seen above mag timing has been checked. Additionally we have
checked shower of sparks (OK) and primer line (OK) but are a bit lost as
to where to go now. Next step might be to pull the primer atomiser from
the blower case and check it is not blocked/damaged.
Perhaps the two symptoms are related - perhaps not?
Any ideas/help on this gratefully accepted!
Regards, Jay
New Zealand
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