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My old Jabiru 3300, when bought new, came with an aenemic Bosch starting motor. As the old starter motor began failing it would barely turn over the engine to start even with a battery fully charged. So I recently replaced the starter motor with the upgraded Nippon Denso starter motor that comes as standard equipment on the newer 3300 engines. With the newer starter motor installed, my 3300 turns over much much faster than it ever did before. The problem now is that my engine will not start or even fire for that matter. It'll just crank and crank and crank and never so much as fire, let alone start.

When replacing the starter motor, I did not have to pull the engine. The only wiring to be done was to run the new starter motor cable between the starter motor and the starter solenoid. Nothing else was disturbed in doing this work. I've since verified that there is adequate fuel flow to the Aeroinjector and that there still is a spark at the plugs. I've subsequently looked everywhere I can think of and find nothing wrong. Up until the starter motor was changed, this was a good running/flying airplane.

I've exchanged emails with Kerry of Sonex and also Jeff Shultz for their input. I've also spoke with Nick, the US Jabiru dealer. While all tried to be helpful by making suggestions of where to look, my engine still does not start. So for now, I've given up. I don't know where else to look.

Has anyone else seen a starting problem like this where apparently turning the engine over faster than before contributes to the engine not firing? I'm open to any suggestions from the rest of you as to what the problem may be.

Thanks,

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

builderflyer wrote:Has anyone else seen a starting problem like this where apparently turning the engine over faster than before contributes to the engine not firing? I'm open to any suggestions from the rest of you as to what the problem may be.

Hello Art,

I do not have a clue but would suggest that the problem is electrical & not fuel related. I had an auto engine do this to me after replacing the points in the distributor. I cranked it but it would not fire at all. I had left the rotor button out of the distributor.

I know you are not that careless but the point I'm after it that it is likely something very simple that is being overlooked. Does it spit, pop, backfire, or anything along those lines? Can you try a small shot of starter fluid to see if it does anything? If not then you can be sure it is in the electrical/ignition system.

I don't see how changing a starter would cause this issue but I don't have a Jabiru ...

Hope you resolve it soon!

Hi Dale, thanks for your response. To rule out the two independent ignition systems, while cranking, I checked for spark at a spark plug while removed but still connected to the ignition wire and held against the engine. I also used a timing light connected in series with one of the spark plug wires from each of the ignition systems. Both tests showed there to be a spark as expected. I also checked the 0.010" clearance between the flywheel magnets and the electronic ignition modules to verify there had been no change in clearance and there was no change. But you are not alone in your thinking............I will try the starter fluid idea just as soon as I get some.

I know it's impossible. There is spark, there is fuel, but the engine does not fire when cranked........no sputtering or anything else. And I was flying the airplane up until the time I changed the starter motor. No other part of the wiring, ignition systems or fuel systems was touched while installing the new starter motor.

Art

Hi Art,

Bob Ohlson here from Florida with a Sonex 3300, You probably have this already but in case you don't on mine I have a ground wire
running from the starter to the airframe and with this ground it made a lot of difference in starting mine.

regards, Bob Ohlson
N528RJ Sonex TD 3300.

Did you have the leads from distributor to plugs off ? If so, it is very easy to read the diagram showing their correct placement as from the wrong end of the engine.

If using the Bing carburetor and had the controls disconnected, the control to the throttle might be set so that it does not fully close. That prevent s the choke from working. You will have fuel, but not enough.

If still no go, might post the problem on the Jabiru/CAMit forum: jabcamit.groups.io/g/main

David A.

Do they make a left and right turning starter? Does your engine still spin the correct direction?

Extremely dumb question. Is your new starter rotating the correct direction?

Thanks fellows, there is no dumb question in dealing with this problem. The newer starter motor turns the engine in the same direction as before, clockwise when viewed from behind. The only difference is that the newer starter motor required a different adapter to engage the starter clutch because it has a smaller diameter gear with less teeth than the old one. This change to my older engine was the same as Jabiru made to the many engines they produced after mine. Jabiru quickly realized that the original Bosch starter motor included with my engine when new never had enough torque to easily turn the engine for reliable starting.

Regarding the ignition wiring........none of this was disturbed in the process of changing the starter motor. Same for the p leads to the ignition modules. The only wiring to be changed was the cable between the starter motor and the starter solenoid.

Regarding the carburetor..........my Sonex has an Aeroinjector and not the Bing. The Aeroinjector had been in tune for the past couple of years prior to changing the starter motor and it wasn't touched in any way while doing this work.

As a test to better isolate the problem I'm going out to attempt to start the engine using starter fluid right after sending this message.

Thanks again, Art

Sounds like a problem you wouldn't expect.
If nothing in the ignition has been touched the extra rpm should only enhance the spark. I have had nothing to do with an aerocarb only a bing. With the bing fuel can cause it to be very finnicky and hard to start if there is a problem with things like the choke circuit or clogged idle jet.
The additional rpm I guess would make using your normal start settings a bit leaner. I'd be looking at a bit more fuel you might just need to be a bit richer at start.

DCASonex wrote:Did you have the leads from distributor to plugs off ? If so, it is very easy to read the diagram showing their correct placement as from the wrong end of the engine.
David A.

At least for the hydraulic lifter versions this confusing drawing was rectified long ago. It is now depicted looking from the back of the engine, not looking through the engine from prop end as it was. It doesnt matter what manual was relevant when the engine was built we should all be using the latest manual from the Jabiru Australian website.

sonex892. wrote:Sounds like a problem you wouldn't expect.

The additional rpm I guess would make using your normal start settings a bit leaner. I'd be looking at a bit more fuel you might just need to be a bit richer at start.

This was my very first thought when the engine wouldn't start. So I enriched the mixture twice with no success before looking elsewhere with no success. Thank you for the suggestion.

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