Lead Fouling on Plugs 912/914Rotax

[HEON]

Have just had to leave my 914 Speed parked a long way from home after a very scary badly missfireing flight on SA purchased Avgas (plugs not very common).

 

On speaking with Bert Floods ordering plugs was told that bad lead fouling is not uncommon in the southern states, especially SA in 914's, running on Avgas.

 

As I have travelled a reasionable amount in Qld, NSW, NT and WA without the problem I was woundering;

 

1. Has any one else had this problem,

 

2. Is Avgas 100LL not the norm "down south"; or different refinery,

 

3. Anyone got an idea why I got such high lead fouling when I commonly use Avgas 100 when traveling "up here".

 

 

[Tomo]

G'day Heon, I found this statement on the web from another person having issues - courtesy of CTAF® by Basscheffers

 

Also I believe SA use 100/130 Avgas still, and are actually lacking in supply due to some of the refineries unserviceable?? Anyone know more about that?

 

The green 100/130 AVGAS is nasty stuff and around Parafield, some fuel-injected C172s are having real trouble with it. Not to mention the Rotax engine in my SportStar, which is why I now fill it with premium unleaded MOGAS, the fuel it was designed for.

Doesn't sound real exciting does it!!

 

Rotax due to being water cooled probably don't get hot enough to burn off the lead, just watch that. One of the main reasons they prefer PULP in them. So if you've inadvertently used 100/130 it could be a problem. (don't quote me on that, but from what I understand you'd wanna be very careful in that area)

 

 

[horsefeathers]

I am not sure how relevant this is to your particular case Heon, but its a good read from a relaiable source re lead fouling...

 

Lead Fouling - Shell Aviation

 

 

[HEON]

That Shell information is very interesting and I personally have not seen it before.

 

It is not a minor problem as it occured to me big time over the Flinders Rangers...not a nice place to have what felt like major engine problems...to me major enought to notify Mel Cen in the Applo 13 words "control, we have a problem!" with lat/long etc as I rearly thought I was going down...did not look a very inviting place to land I must say.

 

Got to a field just east of hills. There found evidence of carby float bowl leaking (resulting in lean mixture)(RA Aus will be informed of occurance/cause) which I have had before that causes the same missing. Fixed that and did extensive flight testing before departing the glide distance of field with no missing thus had no evidance I had not fixed the problem. No problems until 50nm from White Cliffs when all hell suddenly broke loose again.

 

Add approaching evening (airspeed reduced by major degree increasing planned flight time that was fine due to previous stoppage)(yes, had done the maths showing ETA prior to sunset), engine running like a chaff cutter, poor communations not helped by the height I ended up at, and no alternative landing areas before White Cliffs, I was not happy!

 

Have thanked, and would like to go on record, help from Mel Cen (had same person on the line from the morning problems!) and Qantas (flight unknown) for radio relay. Very happy to be able to drink red that night!

 

 

[GraemeK]

Thanks for the Shell article horsefeathers - I'd always been trained to keep the Jabs at around 1400rpm in the holding bay on the first flight for the morning until the oil temperature got into the green. I'd just assumed it was to make sure things were nice and warm before taking to the air - now I know there is another (and maybe even more important) reason to do so. I'll also revise my shutdown procedure.

 

 

[Guest basscheffers]

I doubt very much it would have been caused by a few fills with 100/130, there must be a secondary cause too.

 

100LL fouls the plugs too, just not as much as 100/130. Could it be that it came close to being fouled up before and the 100/130 just pushed it over the edge?

 

How long had you been using these plugs?

 

As far as I know, WA also does not have 100LL, so you would have been fuelling it with 100/130 there also.

 

In any case: do yourself a favour and run it on MOGAS, that's what the engine was designed for! You'll get a better running engine that lasts longer...

 

 

[HEON]

Plugs 70hr.

 

Love to use mogas but to do so it has to be available!

 

Also Rotax says mogas OR avgas

 

 

[Guest Crezzi]

Also Rotax says mogas OR avgas

Rotax only say 100LL avgas

 

Cheers

 

John

 

 

[kaz3g]

Hi Heon and All

 

I know that "rough running" feeling, too. I had trouble between Tennant Creek and the Alice and kept on looking at the road trains and caravans on the highway (school holidays).

 

I too called MEL CEN and the lady operator helped restore some calm in the cockpit. Turned out to be a cracked insulator on a top plug.

 

Soft landings

 

kaz

 

 

[Guest basscheffers]

70 hours - not a lot, unless in that time you've been doing a lot of low-RPM economy cruising use avgas.

 

If you do most of your flying from your home base, you can always consider jerry cans of MOGAS, something even the school at Murray Bridge does. (they have a lot of them!) It's not as easy as calling the refueller or using the bowser, but it saves your engine and probably money too!

 

I use a 6x4 trailer with a single drum on it that I refill every week or two. Some say it's not entirely legal to refill those at petrol stations, but the local Mobil is always happy to see me! (And happy to see I properly earth it...)

 

What oil do you use? Shell Sport 4 is supposed to be the best choice if running leaded fuel. (On the 912 anyway)

 

 

[HEON]

Of course I know Rotax says LL.

 

Please see my first post, item 2.

 

ERSA lists "avgas" for/if fuel available.

 

Being from an area where this is 100LL I was trying to ask where it was not when listed as avgas.

 

Two points:

 

1. Would it not be nice to know what avgas it is BEFORE you arrive,

 

2. It would be nice if some posters gave a person the benifit of doubt that they can/do read the manufacturers requirements on fuel type and inspection requirements.

 

My initial question was for information, and possibly alert pilots that did not know avgas commonly "on tap" available at different locations in Australia was different!

 

For the constructive replies, thank you.

 

For the record;Shell Plus 4 changed prior to departing SE Qld; Always replace plugs at 100hr; I never fly under 5000rpm...I have a Drifter for "slow"; never had evidence of lead fouling on this engine before.

 

If you think I am a bit heavy, sorry, however I know how close I was to putting it down for a reasion I did not rearly know about as the subject had never come up before.

 

 

[Guest basscheffers]

Yup, that's what I do: call. Sad thing is that many times the people that should don't actually know! They too just have the club bowser filled up with "AVGAS" and don't even think about. And these are the same people that fill up their aircraft with the stuff so you would think when checking the fuel they'd take notice of the colour!

 

Anyway, when nothing else is available, I still put 100/130 in there and make sure I run it quite hot. I still don't think in your case it would have been from just a few hours of flying on 100/130. There is a SportStar at Naracoorte that they fuel on 100/130 exclusively and seems to be doing OK. (as in: not failing 70 hours after plug changes, but I doubt they'll make 1500 hours on it.)

 

How long were you in "green" country for? Basically, all of SA is green AVGAS and so is WA. Don't know about NT. All eastern states or on blue 100LL.

 

 

[HEON]

Your last line where LL is not is what we need to know. Note comment on ERSA. William Ck only...what in Broken Hill?

 

 

[Guest basscheffers]

Last time I was there (a year ago) it was 100LL. But then again, a year ago Parafield Shell* (not BP) had 100LL also...

 

So depends on where YBHI gets it from.

 

* and other places they supplied, like Aldinga, YMBD and many stations. They all too are green now.