Slick magneto issue

[tiger26isfinals]

All,

I apologise if this isn’t the right forum but I’m all out of ideas!!!

We have an 0-200 which for whatever reason wont run properly on the left slick magneto. It was removed for a generator change and sent away to be inspected as it was close to 500 hours. The usual parts were changed and on the test rig working fine. However, it still won’t run properly with a bad misfire. The bizarre thing is that with another slick mag on it runs fine! Any ideas greatly appreciated!!!

[Corrosion]

Probably mag internal timing not correct. Sometimes this happens, and it is possible to get it timed with engine but it still not working correctly.

[Ethel the Aardvark]

If your mag was serviced with champion points then I would be resetting the E Gap. For some reason that only champion know their points advance within a few hours of running. We use tempest pma parts now. Whoever did the service should recheck their work.

[NutLoose]

Might sound like sucking eggs but I take it you have tested the plugs, it won't be the first time a plug has gone down during something else like this. I would also be tempted to disconnect the ground to take the switch side of things out of the equation when testing, before sending the mag back.

[Avtrician]

Check the points setting (Egap) and ensure the direction is correct. Double check the drive gears are aligned correctly, a tooth out will make a difference.

[A Squared]

Might sound like sucking eggs but I take it you have tested the plugs, it won't be the first time a plug has gone down during something else like this. I would also be tempted to disconnect the ground to take the switch side of things out of the equation when testing, before sending the mag back.

True, as far as it goes, but the OP did say that the problem disappears when the magneto is replaced with a different magneto of the same type. This seems to rule out causes external to the magneto such as spark plugs and grounding switches.

[tiger26isfinals]

Thanks for the suggestions...I’ll see if they fix it!

[tiger26isfinals]

Following a 500 hour inspection, would the internal timing be checked at all?

Cheers,

Tiger

[NutLoose]

I take it the mag isn't in the batches that were reported of late for internal timing slippage.

Thanks ASquared, missed that.

[Ethel the Aardvark]

Hi Tiger,
not normal to recheck the internal timing after a 500 hr insp.
however, as I mentioned the 3081 points from champion do seem to have a problem,
even if your internal timing was slightly out i woulld expect you would not get the symptons you are describing, it could be any number of other defects, ie distributor finger loose we had a coil wedge loose once causing similar problems but you would hear that rattling around when its fitted, to check if the gear is in the correct position place the timing pin in the correct hole and with the mag in your hand gently wobble the gear back and forth. the points should open and close with a mag tester attached.
we were discovering that at the first check after a 500 hr mag inspection the points had advanced, pain having to remove them again to adjust the egap so we changed to a different brand points and problem gone away,
there was no engine symptons to indicate the incorrect timing
you could always send your mag somewhere else to get a second opinion, should only take 30 mins to have a good look inside and check the basics

[NutLoose]

Send it back, pulling it apart etc will void any warranty claim you may have on the organisation that did the inspection.

[tiger26isfinals]

I checked yesterday and the replacement parts weren’t Champion, as they had the same problems with them as mentioned. It’s going to go back for them to double check over.

[RooDog]

If the capacitor is faulty or not correctly plugged into the points they will burn out pretty quick and cause it to backfire. Check your points, if white and furry replace them and your capacitor. Assuming it was connected properly in the first place.

[tiger26isfinals]

Aren’t aero engines wonderful things!

So it appears that the original mag issue was solved at the 500 hour inspection and the problem since then has been with the cap, which now sorted has us up and running again!

Thanks for all the advice

Tiger