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Where to buy ignition system components

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Where to buy ignition system components

Postby wolfcub1945 » Sat Jul 04, 2020 7:19 pm

I am having problems with the left magneto on my Jabiru 3300 engine. When I conduct the mag check on the right mag there is almost no rpm drop. However, when I check the left magneto the drop is 200-250 rpms and the engine runs very roughly. My A&P suggested installing new spark plugs. I did this, but it did not help. So, a friend suggested replacing the rotor and distributor cap. If the doesn't solve the problem, he recommended installing a new magneto.

Any thoughts on the best strategy to pursue now?

Also, if I need to buy a rotor, distributor cap, or magneto, any places in the U.S. that sell them?

Thanks in advance for your help.

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Re: Where to buy ignition system components

Postby PKnight » Wed Jul 08, 2020 11:01 am

A mag drop of this size is almost always a sign of a fault in the ignition spark to a single cylinder. You know that the fuel supply to the cylinders is OK as the engine runs smoothly on the other mag.
You have changed the sparks plugs so that should not be the source of the problem. There might be a breakdown in the spark from the one magneto so it is possible that the rotor or inside of the distributor needs careful cleaning or replacement.
Check the ignition leads to ensure that there is no sign of a breakdown in the insulation and also check that the leads are securely located in the distributor. I have seen cases where a slightly loose lead looks secure but produces exactly this behaviour.
I would be surprised if the fault was actually in the magneto but aircraft engines can always produce surprises
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