Jab engines

[spacesailor]

This "can" really cleaned my Test engine, Ford 6 pot iron head was clean of all coke-deposits. ran like a watch. after I took the head off to replace a dropped valve, when doing the valve-stem seals,

I wasn't intending to remove the head but ended up that way.

 

spacesailor

[Flightrite]

Not having operated Jab donks much I wonder what is an acceptable amount of oil to be found in the breather collector tank after say 10 hrs of a 2200?

[Roscoe]

Not having operated Jab donks much I wonder what is an acceptable amount of oil to be found in the breather collector tank after say 10 hrs of a 2200?

Not sure about the answer to that, but in my case, at each 25 hour oil change, there is only a tiny amount in the bottom of the bottle.

The secret is not to overfill the sump, and Jabiru recommend keeping the oil level close to the bottom mark of the dipstick for short flights of 1 hour or so.

[Flightrite]

Ok thanks. The best one I operate sometimes is in a conventional u/c design, wonder whether that has any effect on the oil level?

[Old Koreelah]

Ok thanks. The best one I operate sometimes is in a conventional u/c design, wonder whether that has any effect on the oil level?

I often check my oil in both tail-down and horizontal attitudes and never find significant difference.

Edited June 13, 2020 by Old Koreelah

[440032]

We check ours tail down and horizontal often and do find a notable difference. (Same planes, Captain Speaking, you know where.....)

Horizontal full oil = at top mark.

Tail down full oil = half way between the marks.

Nothing much in oil catch bottle after 25 hours. Maybe 100ml, if that.

[Flightrite]

Thanks guys I must check both positions to see any difference.

[kgwilson]

I have heard from a number of pilots that if you fill up to the top of the dipstck the engine will just throw excess out and fill your catch bottle. Jabiru put out a bulletin on oil levels and dipsticks some years ago. It is still on their website. The manual for my Gen 3 3300A says 3.5 litres which I assume includes the oil cooler. My oil cooler is a 7 row Positech which is somewhat bigger than a Jabiru one & is mounted low down on the firewall with about 1 metre hoses. An oil change for me is 3 Quarts which is 2.8 litres and the level is about 2-3mm from the top of the knurled section on the dipstick. At the end of 25 hours it is only another 1-2mm lower & there is only about 20mm of condensate in the catch bottle, no oil as such.

[Flightrite]

Had a look at both positions today, barely a change, very slight. Bottle had 30ml of pure oil in it after 5 hrs, I might have too much oil in the donk, about half way on the knurled section.

[Markdun]

I bought a factory zero timed Jab 2200, to replace the Jab 1600 that I put in the Corby years ago. The replacement was also years ago. When I got the engine I also got the Instruction and maintenance manual. Tyhis gives a good run down on the Bing carbie.

I had mine reconditioned recently and since then it has been running rich, so I decided to lower the needle in the fuel metering system. Easy job, just remove the top and the piston and the needle needs to be turned 90 degrees and moved to the new groove location. That doesn't work, the needle is free turning and will not disengage from the spring clip. Looking down the piston I see a large screwdriver slot, so I remove the screwed in part. Lo and behold it is holding the needle in place and the needle is noting like all the Bing manual depict. There is only one groove for the spring, not 4.

Leith at Jabiru tells me that it has been this way for years, even before my engine was sold to me.

I wonder if anyone else has tried to re locate a needle, or did they have the correct info in the engine manual?

Try a new needle jet instead. The mixture at most power settings is set by the gap between the needle jet and the needle.

I bought a factory zero timed Jab 2200, to replace the Jab 1600 that I put in the Corby years ago. The replacement was also years ago. When I got the engine I also got the Instruction and maintenance manual. Tyhis gives a good run down on the Bing carbie.

I had mine reconditioned recently and since then it has been running rich, so I decided to lower the needle in the fuel metering system. Easy job, just remove the top and the piston and the needle needs to be turned 90 degrees and moved to the new groove location. That doesn't work, the needle is free turning and will not disengage from the spring clip. Looking down the piston I see a large screwdriver slot, so I remove the screwed in part. Lo and behold it is holding the needle in place and the needle is noting like all the Bing manual depict. There is only one groove for the spring, not 4.

Leith at Jabiru tells me that it has been this way for years, even before my engine was sold to me.

I wonder if anyone else has tried to re locate a needle, or did they have the correct info in the engine manual?

The needle jet is brass and can wear from the needle. So if you gradually have increasing richness, try a new needle jet. If that is still too rich, try the next size smaller, then if too lean polish the bore of the needle jet with brasso until you get your desired mixture. This avoids fligging around with the float level.

[Yenn]

That new word aptly describes the means of setting the float level. I reckon it is pathetic. I have just put in a smaller main jet, but haven' flown it yet. It runs OK at full throttle on the ground.

[Russ]

Agreed, Planey. Just trimming it back a smidgeon, within tolerance.

 

Yesterday arvo I poked my inspection camera down the plug holes. Wish I hadn't; up close, the encrustations on top of the piston look like massive geological structures.

I've been religiously using AvGas for a decade, mostly for it's known quality, but would love to get away from lead. Is there any additive I can use to clear those internal deposits?

 

Used Moreys upper cyl lube for yrs, internals clean as.....( avgas used )

[Flightrite]

I use flashlube 1 ml per Ltr 95 RON, engine is running sweet?

[Old Koreelah]

Used Moreys upper cyl lube for yrs, internals clean as.....( avgas used )

So do I, Russ. I guess most of the deposits on my piston crowns are due to running rich.

 

Interestingly, Jabiru tells us not to use any additives in the oil or fuel, but lots of People on the Jab forums seem to ignore that advice.

[Old Koreelah]

My interest in switching to Mogas to avoid lead build ups has evaporated. Just had a look at a mate's fuel system, which recently suffered a potentially catastrophic failure. One fuel hose came off the fitting, spraying petrol all over his cockpit while he was high above Yowie country. Turns out the hose was not very old, but rigid and brittle. It's never in the sun, so we suspect it was due to additives in the Mogas.

[facthunter]

THAT is certainly possible but only use "good" brands of fuel hose. (usually of USA origin). Nev

[kgwilson]

He must be using poor quality fuel line. All mine is good quality automotive fuel hose designed for Mogas. It is 5 years old & due for replacement at the next major service but is still supple & in excellent condition. The clear plastic stuff is useless. Goes brittle really quickly. I used some just for breather tube & the vapours have made it go as hard as a rock.

[Old Koreelah]

...The clear plastic stuff is useless. Goes brittle really quickly. I used some just for breather tube & the vapours have made it go as hard as a rock.

I'd been told that, so tested a length of food-grade clear vinyl tube that I wanted to use as a breather line.

After a couple of years in the sun full of AvGas it was still flexible.

[Roscoe]

I'd been told that, so tested a length of food-grade clear vinyl tube that I wanted to use as a breather line.

After a couple of years in the sun full of AvGas it was still flexible.

Jabiru mandate replacing oil and fuel hoses every 2 years regardless of usage. Ive only ever used Avgas with no issues.

[skippydiesel]

Jabiru mandate replacing oil and fuel hoses every 2 years regardless of usage. Ive only ever used Avgas with no issues.

Rotax recommend rubber replacement every 5 years - I have never used AvGas - use Gates fuel hose on all fuel lines - almost as flexibly, as when new, at 5 years replacement (re cycle my "old" aircraft fuel lines for use on ground based equipment). Gates fuel line all approved for use with Ethanol blends, so no worries there. Gates products readily available through Repco auto stores - haggle to get the best price.

[Yenn]

years ago I bought fuel quality clear plastic hose from an aviation supplier in Orange. About two months later I had a fuel leak in the hose going into the carbie on my Thruster. Had to put it down in a paddock and use the gearbox breather hose to continue the journey. Now I would only use USA coastguard certified hose. Thick and rubber, not clear.

[Bruce Tuncks]

What about the test of hoses where you squeeze them to see if they are still flexible and if any surface cracking happens where the rubber is under tension ?

I have to say I only did this on service points like 50 hours. But now, given the heads up, I will look more frequently so thanks guys.

[skippydiesel]

What about the test of hoses where you squeeze them to see if they are still flexible and if any surface cracking happens where the rubber is under tension ?

I have to say I only did this on service points like 50 hours. But now, given the heads up, I will look more frequently so thanks guys.

Subject to using good quality/reputable hoses - There is no doubt in my mind that the five year replacement interval, prescribed by Rotax, is conservative. However I would rather stick to this than have unseen/internal deterioration potentially blocking filters/jets and/or cracking that allows fuel to spray over hot components. You will not e "cracking" in this insistence but then you are not driving a mower.

[onetrack]

Nitrile rubber, the most common rubber used in hoses, is adversely affected by any level of ethanol in fuel. Nitrile rubber softens and swells, and can be permeated by ethanol in fuels.

 

Many other rubber compounds generally regarded as suitable for fuel are also badly affected by ethanol, even at levels under 10%.

 

Fluorocarbon and Fluorosilicone rubbers are the most durable of all the elastomeric compounds when it comes to resisting the effects of ethanol.

 

As a result, you should utilise these types of elastomers in fuel hoses, gaskets and seals in your engine, if there is even the slightest risk of ethanol being in the fuel you use.

 

Remember also, that service station owners of the dubious morals variety, are often caught adulterating the petrol in their tanks - paint thinners, xylene, methanol, and various other tax-free chemicals are often added by these unscrupulous operators. I would fully expect these dodgy operators to jump on any "cheap" ethanol that became available, so they could add a bit more of it to petrol.

 

https://www.drive.com.au/motor-news/adulterated-fuel-sold-to-drivers-20100823-13gkx

[Russ]

Up until a certain yr ( cant recall that yr ) all jab tanks were sealed with a coating that was not suited for 95..98 mogas. The header tank in particular would leech strong fuel odours..95...98. Resealing them with the later product was the only fix, or just use avgas.