Mogas or Not?

The Jabiru Engine which is used in many other aircraft.

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Willie
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Mogas or Not?

Unread post by Willie » Wed Apr 12, 2017 8:50 am

I am new to the Jabi family. 2004 Model J400 with 3300 engine fitted with an econo kit. So far the only AVGAS was used.
Is it okay to use 95 unleaded?
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Re: Mogas or Not?

Unread post by bullet » Wed Apr 12, 2017 9:26 am

Willie, don`t use mogas unless you have fuel injection. These engines are so light on fuel that the "saving" vs the risk of engine failure when using the single Bing carburettor is not worth it. Do yourself a favour and stick to avgas.
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Willie
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Re: Mogas or Not?

Unread post by Willie » Wed Apr 12, 2017 9:45 am

bullet wrote:Willie, don`t use mogas unless you have fuel injection. These engines are so light on fuel that the "saving" vs the risk of engine failure when using the single Bing carburettor is not worth it. Do yourself a favour and stick to avgas.
It is not about the saving. I need to travel 200km to buy AVGAS, at an above average price. Not convenient at all. No facility to load, offload or store the drums. What is the price of a drumpump? On my Rotax and Lycoming engines there are no problems with their carburetors.
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Re: Mogas or Not?

Unread post by T4flyer » Wed Apr 12, 2017 3:20 pm

Hi Willie,

Do you have a full engine monitor in your Jabi? if you aren't able to monitor each individual EGT & CHT then in my opinion don't even consider Mogas. Mogas generally runs hotter and is definitely more prone to pre-ignition, a real destroyer of Jabiru engines.

If you are able to monitor each individual cylinders EGT & CHT then with a bit of fiddling I can't see why you would not be able to set up your Jabi for Mogas, it has been done before. Don't run the engine to lean, rather run slightly richer and keep the combustion chambers a little cooler.

Always check the colour of the "Mogas" as 95 unleaded should be a nice green colour (Do you remember the "red" supposedly 95 Unleaded Mogas we purchased at the gas station when we were at Hippo pools :shock: :wink: ) purchase from a busy gas station and don't store in a vented container for to long as the fuel octain will decrease.

I run only Mogas in my Jabi, almost 300 hours, no issues. BUT I have EFI and full EFIS to monitor the setup.

Cheers, Don.
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Re: Mogas or Not?

Unread post by buffet » Thu Apr 13, 2017 8:06 am

Hi T4FLYER

You are correct if you monitor all as you said no problem, I have tuned mine and I do a lot of costal flying to the T.
I burn around 14 l per hour all stay nice and cool, but you have get the setup of the carb right.

Willie you are welcome to give me a call I will assist you.

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Re: Mogas or Not?

Unread post by antonvalks » Thu Apr 13, 2017 6:31 pm

When I was at the factory to look at my Jabbi (the one that went flying through the hangar door), I spoke to Len and asked him if it is worth it to convert to fuel injection to save some money by running it on mogas. His comment was: "why don't you run it on mogas? Just make sure you use fresh fuel." According to him a lot of Jabbi's run on mogas without ill effects. But don't follow my advice, rather phone Len and speak to him regarding all the do's and dont's and what the consequenses will be.
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Re: Mogas or Not?

Unread post by ZuluBen » Fri Apr 14, 2017 10:04 am

Been running the UFO on Avgas, Mogas and any mix of those inbetween now for 2 years / 500hrs with no ill effect, save for higher EGT's, especially in the winter.

I am keeping an eye on a Zim Jabbie that ran out of the factory brand new 3 years ago on Mogas and is doing very well indeed. And the quality of the Mogas in Zim is questionable at best.

The Caveat is of course to ensure that the fuel is FRESH. And this is where the problems come, they guys gets lazy / complacent after a while.

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