Jabiru 3300 starting problem

[dboeshaar]

Wow! I'm dying to know how this plays out.
An engine only needs three things to start: Compression, Spark and Air/Fuel

You seem to have checked at least 2 of these.

And brother Murphy is always telling us: "If anything can go wrong, it will" And after 10 years as an auto mechanic, I have often said "I never touched that, I never touched that, I never touched that" and then I see it sitting on the floor.

Please keep us informed!

[builderflyer]

Wow! I'm dying to know how this plays out.
An engine only needs three things to start: Compression, Spark and Air/Fuel

You seem to have checked at least 2 of these.

And brother Murphy is always telling us: "If anything can go wrong, it will" And after 10 years as an auto mechanic, I have often said "I never touched that, I never touched that, I never touched that" and then I see it sitting on the floor.

Please keep us informed!

Before it didn't start I hadn't touched anything but the starter motor and it's cable to the starter solenoid. By now I have "touched" everything in searching for the problem. Even though the timing is fixed, I have now confirmed that it remains at 25 BTDC. I don't pretend to be an engine mechanic but I have been able to keep my Jabiru 3300 running for over 17 years and I've never experienced this before. Still looking and appreciate any new suggestions.

Art,,,,,,,,,,,,,,,,Sonex taildragger #95,,,,,,,,,,,,,,,,,Jabiru 3300 #261/Aeroinjector

[builderflyer]

This was an old problem that was finally solved when a difficult start issue became a no start issue. The left ignition coil was ultimately found to be completely out of spec. The right ignition coil was also found to be out of spec but still marginally serviceable. The mag drop test prior to the last flight was completely normal and the flight itself was routine until it was time to restart the engine for the trip home.

After a couple days of searching for a reason for a no start condition, i finally thought to check the ignition coils themselves. They had got me started for the last flight made, the mag drop test had been normal prior to departure, the engine operated normally for the flight...........how could the coil(s) be bad. But as noted above, they turned out to be the source of the no start problem. Fortunately, I had a spare ignition coil to replace the left one and as soon as it was installed the engine fired right up and ran normally.

Nick, from Jabiru Tennessee, recommends using the Honda ignition coil. So I've ordered one from him and will use it to replace the marginal right ignition coil. The no start or difficult start matter appears to be gone............finally.

Art,,,,,,,,,,,,,,,,,,,,Sonex taildragger #95,,,,,,,,,,,,,,,,,Jabiru 3300 #261

[Kai]

During my trials and tribulations getting the Jab ignition modules to work as advertised, I found four things of vital importance:

They had to be cooled by blast tubes in flight as suggested in the engine installation manual.

Introduce some sort of openings in the cowling top over the modules to ensure air circulation over them as soon as the engine is stopped after flight.

Always park the plane out of direct sunlight, preferably in shade.

Use only the best coils from reputable sources. While Camit was still in business, theirs were excellent.

My two bits
Kai

[sonex892.]

Use only the best coils from reputable sources. While Camit was still in business, theirs were excellent.

My two bits
Kai

I used a Chinese one once It didnt fail for at least 2 months. I now use only Honda, I have had to remove and change the coil lead. I'm sure Jabiru and camit did the same.

Too large a gap on the magnetron to magnets will also make Jabiru's harder to start. It is a very tight space to check this on a 3300 Sonex.

[builderflyer]

During my trials and tribulations getting the Jab ignition modules to work as advertised, I found four things of vital importance:

They had to be cooled by blast tubes in flight as suggested in the engine installation manual.

Introduce some sort of openings in the cowling top over the modules to ensure air circulation over them as soon as the engine is stopped after flight.

Always park the plane out of direct sunlight, preferably in shade.

Use only the best coils from reputable sources. While Camit was still in business, theirs were excellent.

My two bits
Kai

Kai, all of your suggestions are spot on. Early on I burned out two ignition coils because the blast tubes used were not large enough to do the job. As you know, the ignition coils do not burn out in flight. They burn out immediately after flying because that's when they are exposed to the highest temperatures. Your idea to vent the cowling above the coils is an excellent one.........I've just never come up with the best way to accomplish this so I open.up the oil fill door instead.

Art,,,,,,,,,,,,,,,,Sonex taildragger #95,,,,,,,,,,,,,,,,,Jabiru 3300 #261

[builderflyer]

[
Too large a gap on the magnetron to magnets will also make Jabiru's harder to start. It is a very tight space to check this on a 3300 Sonex.

Steve, my 3300 was built before Jabiru decided it would be a good idea to true up the magnets on the flywheel. That is, the magnets on my engine are not all exactly the same distance from the center of rotation. That, obviously, makes it impossible to maintain the recommended 0.010" clearance from each magnet. So I had to first determine which set of magnets were closest to the ignition coils and use them to set the clearance. Otherwise, when setting the clearance using a different set of magnets, physical interference with the closer set of magnets would occur. Not good.

Art,,,,,,,,,,,,,,,,,,,Sonex taildragger #95,,,,,,,,,,,,,,,,,,Jabiru 3300 #261