Engine that does not turn round full throttle

[Loiret39]

Hello everyone. My engine now 130 hours and so far worked perfectly well.I fly on two ignitions when I take off and when I land.In cruise I cut the second ignition in order to consume less current and to better recharge the battery.In cruising at 2800 rpm there is no problem with only the first ignition on. For some time, when I am on primary ignition alone and I put full throttle, the engine does not take its turns and "stuff". Simply turn on the second (electronic) ignition and all will return to normal.I changed the spark plug and it re-worked an hour before I started again. I turn with a rather rich mixture (the spark plug are black and there is depot in the exhaust).
Do you have any idea about this?
Thanks for your help
André

[Loiret39]

Hello all,
i always have the problems with the primary ignition.the primary ignition does not allow the engine to run properly.
With new spark it's OK for just an hour.as if the ignition was not powerful enough. I thought of a worry with the primary ignition magnet (mounted upside down or demagnetised).
Would anyone have an idea?
Thanks for your help
André

[Sonex1517]

Hello all,
i always have the problems with the primary ignition.the primary ignition does not allow the engine to run properly.
With new spark it's OK for just an hour.as if the ignition was not powerful enough. I thought of a worry with the primary ignition magnet (mounted upside down or demagnetised).
Would anyone have an idea?
Thanks for your help
André

Andre

I would suggest you check the orientation of your magnets.

[MichaelFarley56]

Andre,

In addition, it may be a good idea to check that you have the correct spark plugs installed in the top of the cylinder heads. If you have incorrect plugs, or if they're not gapped properly, that could possibly lead to your issues. The power the different ignition systems produce results in the need for different spark plug gaps; refer to your engine assembly manual for the specifics.

Best of luck!

[kevinh]

(I'm the opposite of an expert on this topic but...) what about checking the 0.010" gap for the mag pickups?

[sonex1374]

Andre,

It definitely sounds like the primary ignition is not firing properly at full throttle with the rich mixture setting you currently have. This could be caused by partially degraded ignition components. You mentioned that the problem goes away with new spark plugs, but starts up again after just an hour or two of run time on the new plugs, and that the plugs are dark black and sooty.

We can brainstorm ways to make the ignition system more powerful, or to correct a problem within the components, but is it possible that you're simply running too rich at full throttle to keep the plugs working properly? A properly adjusted AeroVee does not need to be run so rich as to foul the plugs with black soot, and I think that's your real problem.

Try running at full throttle for 10 minutes with both ignitions turned on, but leaning the mixture a bit to burn off the black carbon from the plugs. If the plugs are clean, the primary ignition should operate properly, and you can verify this by turning off the secondary after that 10 minute test. If the plugs are good and clean but the problem remains, then you may have damaged ignition components that need to be identified and replaced. My first thoughts are: check the magnetrons for signs of scraping along the bottoms by the trigger magnet cover plate (rubbing will overheat and destroy the magnetrons); possible damage to the trigger magnet that has lowered the strength of the magnet (note that a damaged magnet might still have some pull, just not enough to work properly); or damaged spark plug leads or plug caps.

If you need to keep the mixture very rich to prevent the engine from overheating, then that is a separate problem you need to address. You'll need to look at your cooling airflow, oil cooler and cowling inlets/exits.

Jeff

[mike.smith]

Bad ground connections?

[Loiret39]

So in first , thank you all for your help.
Tonight i made some vérification on my engine.
The orientation of the magnet is good
The calibration between the magnet and the magnetron is 0,25 mm (sorry i'm french!)
The ground is OK between the two magnetron, the engine, and the battery ground.

I wanted to do a test to deplete the mixture.I turned a quarter turn clockwise the needle. the problem with the primary ignition persists and moreover the engine is struggling to take turns during a fast acceleration. it crap. it' impossible to fly with this setting.

how to have a correct mixture and a less rotating engine?

Is it possible to have an electric spark wired worn. and have a parts of the electric power go on the groud?
Is it possible to change the spark wire on the magnetron?
Regards
André

[Loiret39]

UP ?

[Onex107]

Sounds like fouled plugs. I had that problem with a rich setting. Bits of carbon were flaking off the piston and fouling the plugs. With the fuel adjusted properly, the plugs should be clean.