David,
Most likely, one (or both) mags are not being properly shorted to ground when
switched
off. Do you get a proper mag check? That is, do you get a RPM drop when
you check Mag A and Mag B individually on your run up mag checks? If you
do not, then one of the mags has a bad ground wire. If you do get a proper RPM
drop on both Mags, then your switch does not properly ground one or both mags
when switched off. Check the switch connections in the off position to make
sure both mag wires have continuity to ground.
Let us know what you find.
Great flying,
Bob Borger
On Wednesday, December 05, 2007, at 03:12PM, "David Joyce"
<stranfaer@btinternet.com>
wrote:
>
>We have of late been experiencing a run on with the engine after switching
>off!
>The only way we have been able to shut down has been by turning off the
>fuel.
>
>It does not do it evrytime, however the instances are becoming more
>frequent, I have only subscribed to the list for just over a year and dont
>recall any other instances?
>
>However if there are any ideas or suggestions I would be gratefull?
>
>rgds
>David J Joyce B-BWON
>
>
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