an interesting in flight experiment

Next time you're at altitude and in cruise mode, switch from 'both' to
a single bank of spark plugs. It will remind you what happens should
you have one side decide to go in/op when in flight. I had the engine
(IO 360) go rough a couple of weeks ago, but rough was a lot better
than the very smooth and silent effects the left mag only gave me.

"a" wrote in message
...
Next time you're at altitude and in cruise mode, switch from 'both' to
a single bank of spark plugs. It will remind you what happens should
you have one side decide to go in/op when in flight. I had the engine
(IO 360) go rough a couple of weeks ago, but rough was a lot better
than the very smooth and silent effects the left mag only gave me.

Sounds like at least two problems--unless the fault was in the switch.

Peter
Just a thought

On Oct 17, 3:01*pm, "Peter Dohm" wrote:
"a" wrote in message

... Next time you're at altitude and in cruise mode, switch from 'both' to
a single bank of spark plugs. It will remind you what happens should
you have one side decide to go in/op when in flight. I had the engine
(IO 360) go rough a couple of weeks ago, but rough was a lot better
than the very smooth and silent effects the left mag only gave me.

Sounds like at least two problems--unless the fault was in the switch.

Peter
Just a thought

Nope. Engine went rough, stayed just as rough on the right bank, too
quiet on the left. After the repair all was well
again.

Even on run up you lose some RPMs when on a single bank of spark
plugs.

"a" wrote in message
...
... Even on run up you lose some RPMs when on a single bank of spark
plugs.

If you don't get an rpm drop when running on a single mag, something's
probably amiss. My engine has never run rough during a mag check, except
when I forgot to lean aggressively before taxi and got lead fouling.

Jon Woellhaf wrote:
"a" wrote in message
...
... Even on run up you lose some RPMs when on a single bank of spark
plugs.

If you don't get an rpm drop when running on a single mag, something's
probably amiss. My engine has never run rough during a mag check, except
when I forgot to lean aggressively before taxi and got lead fouling.


Long ago I had rented a C=150 that the run up mag check was fine before
a return flight back to the home airport (about 1 hour flying). All of a
sudden in cruise the engine was running rough. I did a mag check, on one
side was rough and the other side smooth. I elected to run on one mag
that was good and squawked the aircraft upon landing.

--

Regards, Ross
C-172F 180HP
Sold
KSWI

Ross schreef:
I ... squawked the aircraft upon landing.

Ross, what do you mean by "squawking a plane upon landing?"
I only know the verb in a transponder context.

a wrote:
....
Even on run up you lose some RPMs when on a single bank of spark
plugs.

Usually. At a 1700 rpm run up this morning, - I couldn't find a
drop either side. So I did a dead cut (at 1200rpm) with the usual effect.

Brian W

This test should be part of the run-up pre-flight check.

You are verifying that the P-lead correctly grounds the magneto (by
observing the drop)
and that the firing side is operational. You are also, of course, verifying
that the engine will run on the ungrounded side (and that it is firing that
entire bank of spark plugs by scrutinizing how well it runs).

I am sure you know all of this (grin), I just chimed in becuase its a check
best done on the run-up pad.

Todd

"Peter Dohm" wrote in message
...
"a" wrote in message
...
Next time you're at altitude and in cruise mode, switch from 'both' to
a single bank of spark plugs. It will remind you what happens should
you have one side decide to go in/op when in flight. I had the engine
(IO 360) go rough a couple of weeks ago, but rough was a lot better
than the very smooth and silent effects the left mag only gave me.

Sounds like at least two problems--unless the fault was in the switch.

Peter
Just a thought

"twdeckard" wrote

I am sure you know all of this (grin), I just chimed in becuase its a
check best done on the run-up pad.

He did not say you shouldn't do it at run-up. He was just pointing out
that your engine could run very rough if you lose one side while cruising.

--
Jim in NC

I didn't mean the post to sound too pedantic. I guess I reacted to the OP
phrasing it as a question or a suggestion. I am sure it was rhetorically so
....


"Morgans" wrote in message
...

"twdeckard" wrote

I am sure you know all of this (grin), I just chimed in becuase its a
check best done on the run-up pad.

He did not say you shouldn't do it at run-up. He was just pointing out
that your engine could run very rough if you lose one side while cruising.

--
Jim in NC