All About Magnetos 

1:35 Components and Operation 14:15 Common Failure Modes 20:59 Magneto Timing (Internal and External) 25:14 Starting (Impulse/Snapper Coupling, SOS) 32:43 Mag Checks 38:52 High Altitude Operation 43:44 500 Hour Inspection IRAN 46:11 Mags Makes and Models 49:48 Trouble Shooting 52:07 Questions

I am working on getting my A&P and this video has been great. Thank you!!!

Excellent film footage and sound. Great tutorial for refresher.

As a Certified Mechanic I rebuild and service a lot of magnetos. Many times I have had to replace the entire rotor due to corrosion on the magnet & shaft so severe that the shaft broke in two pieces after pulling the bearings off. Worse is neglecting the magnetos by not flying the aircraft due to neglect of routine maintenance & annual inspections regardless of time on the engines. Such neglect will have you paying more in the long run and your aircraft's value decreases substantially.

Thanks for the time you spent making this video

Mike ROCKS!!

Great seminar!

Excelente explicación gracias hermano

Thanks again

I disagree with 500 hour IRANs, every magneto I've opened has moderate to severe burning on the electrode fingers, and the assembly alone is like 500 dollars for this, the carbon brushes I see are always way within limits. Add in a contact point kit which is like 200-300 dollars and you already meet the cost of receiving an overhauled magneto often times. You also have to take into account the time it takes to perform a 500 hour magneto inspection as opposed to just changing out gears if necessary and installing overhauled magnetos. If you go off of the overhaul manuals, you will often find enough stuff in a 500 hour magneto that exceeds the cost/time of changing out internal components as opposed to getting an overhauled one.

This can be watched at 1.5x speed very comfortably

I’ve had a very unusual snag on my Franklin 150 engine equipped with Bendix S6RN-21 mags. The engine runs smoothly at idle up to about 1700 rpm where it starts running very rough to the point where I have to pull the throttle. I’ve changed the plugs, the carburetor and both magnetos. Fuel flow is 35 g/hr ( recent fuel) and compression is over 76/80 on all cylinders. Could components like capacitor or coil create erratic ignition at high rpm?

Would it not be a reasonable thing to verify the timing of point break on both lobes of the cam during the 500hr inspection?

Can a bad tuning Magnetos cause engine vibration? Thank you

It does not matter, either a battery & coil ignition set-up or a magneto, even the model; T coils in the wooden boxes had a condenser in them, the condenser being wired across the points of coil's vibrator. juice came from the "MAG' which was a low voltage magneto, V magnets spun past a series of coils in the bellhousing or shroud or from a battery of either a number of #6 dry cells or a wet lead acid type battery. a switch was for MAG or BAT/OFF and a commutator type switch worked each coil.

It's interesting how the design of aircraft engines has lagged behind current engine technology. Cars have electronic ignition, some don't even have distributors or a single ignition coil. Now I realize that a computer needs a separate power supply incase of an alternator or battery failure. Electronic ignition does exist in aviation but it's experimental and is usually pared with a mechanical ignition system for redundancy.

Hi mike, my name is mike busch are you my evil twin? Like your video!

Por favor alguien que me dé información para partes de Magneto Bush para motor de 2 cilindros

thank you sir

Mike, I've been searching for an expert in this field and so i found you. I fix small engines both 2 & 4 cycle in the lawn care industry. I heard of a problem, have not seen it for my self, but am very very curious what could be the cause. So here it goes. My friend got a Stihl chainsaw that would bogg down.He saw the culprit to the problem as there was a spark between the magneto/coil and the magnets on the flywheel which was in direct correlation with the bogging down-the spark got stronger as he tried to rev it up then the engine boggs down. He then purchased both a new flywheel and coil from Stihl and still has the same problem. How is this spark, in that location, possible and what can be done to diagnose and/or fix it? I have never seen or heard of such I thing as I have repaired small engines for a long time. It would seem to mean there is a leak or bad ground possibly? What are your thoughts?

Busco Magneto para motor de dos cilindros

Mike we must place ,new knowledge to get rib off the magneto point and Condenser, and use the impulse , system used on high performance Automobile engine ,is much much better than the point condenser set up

At about 33:04 you mention Lycoming's Service Instruction 1132B and state the instruction now requires lean to peak while performing the mag check. But that's not exactly what it says. You're to start with full rich but if you have a drop of more than 175, then you are to go lean and repeat (am I reading the SI correctly?) www.lycoming.com/sites/default/files/Magneto%20Drop-Off.pdf

Mike are u there?

Assuming your engine is modern enough to have the capability to lean it.

YUP. the condenser absorbs the inductive kickback of the primary circuit being open. This condenser will always bee seen in any ignition circuit using 'points' like in an auto ignition coil using 12 volts or an H4 magneto on a farmall tractor.

Started as very informative but the credibility was lost on real practical questions. I have a Continental A-75 with no impulse on either magnetos and it starts with no extra effort than the ones with impulse at our field. Also, Slick Mags are popular for a reason and I don't agree that aviation community (by majority) will switch over to the 'less robust' product just because its cheap.