Author Topic: AUSTRAL RUNNING PROBLEMS.  (Read 988 times)

Austral

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AUSTRAL RUNNING PROBLEMS.
« on: 03 November, 2019, 12:38:30 pm »
Our club is custodian for a 6hp magneto start Austral which is in very good mechanical condition and starts easily, but will run down and stop after some time. The time can vary from a few minutes to over an hour.
The magneto gives a strong spark and the fuel (petrol)  supply is continuous. We have tried numerous spark plugs of different heat ranges and brands, but the problem persists.
 I have thought that possibly when the engine warms up, the vaporizer may be creating a vapor lock situation, but the variation in time seems to contradict this. The run down can occur when both hot and cold as evidenced by the time variance, and at this stage we have not tried kerosene.
My question is:
Do other magneto start Austral owners have this problem when running on petrol, and if so, how do they fix it?


Austral

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Re: AUSTRAL RUNNING PROBLEMS.
« Reply #1 on: 17 November, 2019, 12:37:15 pm »
Well now, here we are two weeks down the track with ninety odd views but not one solitary reply. Perhaps no one out there has experienced this problem and therefore has no idea of how to correct it. Maybe it will have to remain as one of life's little mysteries.

famous fitter

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Re: AUSTRAL RUNNING PROBLEMS.
« Reply #2 on: 17 November, 2019, 12:50:44 pm »
Hi Austral.
Maybe just start it on petrol and run it on Kero - like it?s meant to. I know of another one that the owner spends all day changing spark plugs but refuses to run it on Kero for some reason.

The intake mixture is too crude and from experience they run too rich on petrol and foul up.
 
They are a petrol start oil engine not a dual fuel engine !!!!

Cheers Justin

Holden

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Re: AUSTRAL RUNNING PROBLEMS.
« Reply #3 on: 17 November, 2019, 03:12:50 pm »
Hi there,
I own a 6 HP Austral.  Have had similar problems to you.  Firstly the kerosene you get today is more for lighting, not power kero.  I use a champion D21 spark-plug because it is the hottest and most easily available.  I start mine on petrol and use a 50 - 50 mix of petrol and diesel in place of the kero.  Also had to make the fuel jet approx half as small as it was and doing this it should run all day without fowling the plug.  It depends on the load of the engine, of course.
Hope this helps.
cheers Holden

John 54

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Re: AUSTRAL RUNNING PROBLEMS.
« Reply #4 on: 17 November, 2019, 06:10:22 pm »
Hi All
These engines were designed to run on lighting kero not power kero. Power kerosene was formulated for spark ignition, look at tractors and small engine that run on power kerosene they all have spark plugs, and are spark ignition, power kerosene has not been available since the 1960's. Australs were never designed to run on petrol or power kerosene, the Magneto engines were introduced because Ronaldson & Tippett were losing sales to cold start diesels. The engines were only ever meant to be started on on petrol and once hot run on kero and the magneto turned off ( that is why it has the mechanism to stop the magneto), you can hear when the engine stops needing the magneto, it runs smoother. The engine is jetted for kero not petrol, magneto engines and lamp start engines use exactly the same jetting.
That is why spark plugs are a problem. If Ronaldson & Tippett had intended these engines to run on power Kerosene and/or petrol why not remove the timing valve and why add the exhaust circulation to the hot box (all designed to make the engine more efficient on lighting kero).
Regards John
John

Austral

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Re: AUSTRAL RUNNING PROBLEMS.
« Reply #5 on: 18 November, 2019, 09:53:16 am »
Hello Justin, Holden and John 54,

Thank you for your replies and each is taken on board. I completely agree with Justin and John in the fact that the Austral side shaft engines were designed to run on kerosene and that is how it should be. I think the idea of trying to run them on petrol is purely based on economic reasons due to the exorbitant price of kerosene these days.
Fortunately, with my own Austral I don 't have the problem. It is a lamp start and runs perfectly all day on the igniter coil after  12 to 15 minutes warm up with the Primus lamp. 

Regards,

John.

cobbadog

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Re: AUSTRAL RUNNING PROBLEMS.
« Reply #6 on: 18 November, 2019, 10:03:35 pm »
Regardless of the cost, it would be worth a try to see if this is your problem, it is the only way to find out. If it does run on the kero then you have solved it and if it doesn't you need to look else where or try re jetting as has been posted. If this is the way you need to go It was suggested to me recently that to down size a jet they filled the hole with soft solder and re-drilled it smaller, crude but worked.
Cheers, John & Dee. Coopernook. NSW.

John 54

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Re: AUSTRAL RUNNING PROBLEMS.
« Reply #7 on: 19 November, 2019, 08:18:14 am »
Hi All
It is not just a matter of re jetting. On the inlet stroke of an Austral a very rich mixture of fuel and air is drawn into the "hot box" and air into the "combustion chamber" above the piston. When the piston starts the compression stroke the timing valve closes, the timing valve then opens just before TDC ( whatever the advance is) and the spark plug fires. When the timing valve opens the very lean mixture from the "combustion chamber"enters the "hot box"just as the spark plug fires. The problem is what is the mixture like at the spark plug which is next to the timing valve, is it rich, lean or just right.
As I see it the only way to get the correct mixture at the plug is to not let the timing valve close or remove it, and allow minimal or no air through the air valve. This will cause the engine to drew a more consistent fuel air ratio into the engine through the fuel valve. (This is what most people who run the magneto all the time do by proxy they close the choke.) The problem here is that the fuel valve is so small that not enough fuel/air can be drawn in, so the engine will never run properly.
Ronaldson Bros & Tippett built a couple of gas engines for there own use ( to drive line shafts) they took an Austral oil engine removed the hot box assembly from the engine and fitted an ignitor in its place it was driven off the timing valve cam. Pictures of this engine are in the archives in the State Library.
Regards John           
John

Austral

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Re: AUSTRAL RUNNING PROBLEMS.
« Reply #8 on: 19 November, 2019, 11:19:34 am »
Hello cobbadog,

Of course it will run on kerosene, that is what they were designed to do following a petrol start. You may not be aware that the change to kerosene is automatic. As petrol in the fuel trap is used up, it is replaced by kerosene pumped from the main tank and this process begins as soon as the engine is started. 
If you refer to my initial post, you will see that it questions what various owners do to prevent stopping when trying to run them on petrol.
 I think John 54 has explained it perfectly.   

Austral.

cobbadog

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Re: AUSTRAL RUNNING PROBLEMS.
« Reply #9 on: 19 November, 2019, 02:30:46 pm »
Cheers
Cheers, John & Dee. Coopernook. NSW.

Austral

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Re: AUSTRAL RUNNING PROBLEMS.
« Reply #10 on: 27 November, 2019, 09:01:46 am »
Hello Holden,

When running on the mix of 50/50 diesel and petrol, do you still use the magneto or take it out of action and let the engine run on the igniter coil in the vaporiser? In other words, does this mixture vaporise like kerosene? 

Austral.

Holden

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Re: AUSTRAL RUNNING PROBLEMS.
« Reply #11 on: 25 May, 2020, 10:26:54 am »
Hi Austral,
I run it with the magneto in operation, can't seem to get enough heat into the engine to run without the magneto.
Holden

John 54

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Re: AUSTRAL RUNNING PROBLEMS.
« Reply #12 on: 25 May, 2020, 12:10:24 pm »
Hi Holden
A few things first. What coil are you using? is the hot box clean (no carbon inside as carbon is an insulator), have you tried running with the timing valve open all the time?
Try holding a rag hard against the flywheel to make it work and get it hot.
regards John

 
John

Eric Schulz

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Re: AUSTRAL RUNNING PROBLEMS.
« Reply #13 on: 25 May, 2020, 12:35:00 pm »
The Austral gas engine.

Eric