Rotax 912 5 Year Rubber Replacement

Having just completed my 912 ULS, 800 hr & 5 year rubber replacement, maintenance/ service, I just thought I might share my hose supply experience with you:

 

My coolant, fuel & oil hoses come from only two suppliers Gates (Repco these days) and Bert Flood.

 

BF supplies my oil & small coolant hoses.

 

Repco supply my Gates large coolant & all my fuel hoses.

 

Gates specifications & Part No are:

 

Fuel

 

27349 - 3/8 (9.6mm) Barricade Fuel Injector Hose

 

27348 - 5/16 (7.9mm) Barricade Fuel Injector Hose

 

27347 - /4 (6.3mm) Barricade Fuel Injector Hose

 

Above part numbers are for 15 ft length, however Repco will sell it to you by the metre. (The FI hose is about twice the price of ordinary low pressure carburetor hose)

 

I use proper fuel injector hose clamps for a good seal without damaging the hose.

 

My fuel filters are Hengst H 102 WK (for those who might want an inbuilt elbow, try H 103 WK)

 

 

Coolant.

 

Radiator hose Pn 05-0725 (x 3) . Three of these Holden Barina MF 1.3 L 1989-90 upper radiator hoses do my installation very neatly with minimal cutting & only one joiner

 

Joiner 90 degree elbow Pn 28626 (x 1). These joiners come in a pack of two. They may look similar to 1" plastic irrigation line joiners but are properly heat rated and tested for coolant compatibility.

 

Coolant concentrate is Castrol Radicool mixed 50:50 with distilled water.

 

If you want straight joiners the PN is 28606.

 

I have attached a photo of the coolant hoses & connectors, with two other hoses I did not use.

 

The unused hoses are:

 

PN 05-1797 Subaru Outback 3.0L 6 cylinder 1988-04 Upper radiator

 

PN 05-1235 Ford Lazer 1994-96 Lower radiator

 

 

For a nice clean cut, invest in a pair of cheap hose cutters (a little spray of silicon on the blade helps the cutting process)

 

 

 

 

Thanks, good info there

 

 

Thank you for sharing the results of your work, some good info there. Re the fuel hose though.....injection hose may not be a better choice than standard carburettor hose according to the Rotax Owners website....

 

"The good thing with the standard carburetor hose is it has a little give in it since it isn’t as stiff and rated for the higher fuel injection pressure. This hose will slide over the flared, bulb or barbed fittings much easier and there is far less chance of scraping the inner liner and causing unwanted debris. A smooth inner liner is more preferable than a raised criss-cross pattern on the inside of some fuel injected hose which is caused by the thread re-enforcement of the hose. This tends to scrape more with a barbed fitting. I know everyone remembers that our normal 912 fuel system operating pressure is up to 2.2 to 5.8 psi for the 912UL or ULS engine. So let’s just say the upward limit is 6 psi to round it off. So using the standard carburetor hose works just fine with plenty a pressure safety margin."

 

 

Hi Hugh,

 

I am pleased that my experience might benefit you and other Rotax 912 drivers.

 

I do not disagree with your point "injection hose may not be a better choice than standard carburettor hose" - my selection of Gates FI hose for my fuel lines is probably more psychological than functional. However I would point out the slightly lower permeability and marginally higher temperature rating of of Gates FI hose compared with their carburetter hose. Of course this is just my rationalisation of the irrational. Still it makes me feel good and I am certain the rather speculative sounding reference by Rotax Owners to "unwanted debris" resulting from using FI hose does not apply to the excellent Gates products that I have used, without issues, for many years.

 

My inline fuel filters (the Hengst filters are transparent allowing good visual assessment for filter contamination) ) and preflight tank draining rarely have foreign material contamination of any description. In fact I reused my "boost" pump filter after a quick reverse blow through and even considered doing the same with my main fuel line filter but in the end elected to replace it with a new unit. The retired filter is now serving as a prefilter on one of my ground based diesel engines.

 

 

skydrive uk will sell you 17mm hose at GBP15/metre. Still quite competitive I think.

 

To work the clips you want the hose pliers at Angled Flat Band Hose Clamp Pliers Rotax 912 582 Aircraft Auto Engine Coolant | eBay. Makes it all a breeze rather than mucking about with ordinary pliers and vice grips. Nothing like the right tool for the job.

 

 

skydrive uk will sell you 17mm hose at GBP15/metre. Still quite competitive I think.To work the clips you want the hose pliers at Angled Flat Band Hose Clamp Pliers Rotax 912 582 Aircraft Auto Engine Coolant | eBay. Makes it all a breeze rather than mucking about with ordinary pliers and vice grips. Nothing like the right tool for the job.

I take it this is the small coolant hose?? Seems a bit pricy at about $26/m. The pre curved/bent radiator hose I purchased at about $20 each.

 

 

I take it this is the small coolant hose?? Seems a bit pricy at about $26/m. The pre curved/bent radiator hose I purchased at about $20 each.

Now I am confused. Was that $20 each from Bert Flood? As I recall we bought a kit like that for about NZD125 from ConAir in the UK which was under half what the Rotax people wanted for the real thing. If you go to the ConAir site now you find that they have passed their hose stuff to Skydrive who only sell 17mm hose by the metre. I was not able to find 17mm hose anyplace else .... I know of people who tried 18mm (leaked) and 16 mm (could not get it on) and something/16". For whatever reason, the boys in Austria went for 17mm ...

 

 

For the benefit of us Jabiru types, what is the total cost of parts needed for a big Rotax service which includes rubber replacement ( and other things I guess).

 

How long does it take to get parts from Austria ? Is the postage horrendous like it is from the US?

 

 

Now I am confused. Was that $20 each from Bert Flood? As I recall we bought a kit like that for about NZD125 from ConAir in the UK which was under half what the Rotax people wanted for the real thing. If you go to the ConAir site now you find that they have passed their hose stuff to Skydrive who only sell 17mm hose by the metre. I was not able to find 17mm hose anyplace else .... I know of people who tried 18mm (leaked) and 16 mm (could not get it on) and something/16". For whatever reason, the boys in Austria went for 17mm ...

Okay - just got my BF invoice out -

 

Water Hose 17mm - $55/m (strangely BF sells it by the cm)

 

Formed Hose 90 degree 17mm - $32.26

 

Oil tube - $44/m (again strangely sold by 1.5m)

 

(All prices less 10% GST)

 

So BF is charging way over your British quote for 17mm water hose - my apologies.

 

I was lazy when it came to this 5 year rubber change and didn't research alternative supplier/costs but then I received my order within a day or so without any worries about payment/material quality & compatibility. I guess I have paid "handsomely" for the convenience.

 

My Gates 25mm formed radiator hose PN 05-0725 were $12 each from Repco (I used three).

 

The Gates 25 mm joiners 90 degree elbow PN 28626 were $8.70 pack of 2 (I used one). The straight joiners PN is 28606.were $5 again for a pack of 2

 

".......16 mm (could not get it on)....." I am surprised that the 16mm hose would not stretch over the 17mm spigots.

 

 

For the benefit of us Jabiru types, what is the total cost of parts needed for a big Rotax service which includes rubber replacement ( and other things I guess).How long does it take to get parts from Austria ? Is the postage horrendous like it is from the US?

Hi Bruce -

 

My "Rubber" from BF was $750 (inc GST/ less post) but as is my want I over ordered on 17mm water and oil hose. So you could knock offt $50+ for hose that is now "on the shelf" .

 

My bill from Repco (Gates fuel & 25mm radiator hose, plus 2.5 litres Castrol Radicool coolant concentrate) was $235. Again I have quite a bit of FI hose "on the shelf"

 

Other expenditure would be - quite a lot of cable ties, some automotive conduit & insulating reflective tape. High quality silicon grease & other consumables used in reassembly. Most of the "hardware" hose clamps etc was reused although by careful planning & cutting I managed to delete some brass hose joiners from the system.

 

A fair bit of bad language and blood was generated.

 

NOTE: I have not included routine engine service costs (oil/filters/spark plugs, etc)

 

 

Mackay rubber here in Australia make 17.5 mm works well.

 

 

With my 17 mm (small) coolant hose replacement, I cut my hose (long) so that it will stay in place without the need for the hose clamps. The clamps provide sealing under pressure. My guess is that most if not all owners would do the same. Hoses (& all "rubber" components) are fitted using a smear of Molykote 111 silicone grease on the spigot.

 

 

Mackay rubber here in Australia make 17.5 mm works well.

Mackay Part No HH1752 is a 2 metre pack of 17.5mm hose. Paid $15.45 three years ago.

Mackay Part No CH3752 is a molded 17mm 90 deg bend which can be cut to size for the bent hose. Paid $25.50 three years ago.

 

 

I used silicon hose for the bends and rotax 17mm hose for the straight sections under the heads.

 

16mm/25mm silicon fits perfectly.

 

 

I used silicon hose for the bends and rotax 17mm hose for the straight sections under the heads.16mm/25mm silicon fits perfectly.

Have never used silicon hose in an aircraft application. I would welcome your observations on the following:

 

Silicon hose is:

 

• relatively heavy when compared with conventional hose
   
   
  
• quite soft & flexible hence the 16mm hose fitting over the 17 mm spigot and its (25 mm) ability to conform to quite tight radius bends
   
   
  
• purported to have a long service life but that this does not negate the requirement (by Rotax) for a 5 year replacement
   
   
  
• costly compared with conventional hose
   
   
  

 

 

 

 

Weight.... doesn't seem heavy at all. If it is we're talking a few grams.

 

Strength. Has reinforcing imbedded in it so is quite strong and ridgid.

 

I purchased pre-molded elbows at various angles as bending straight sections too far caused a "kink", as an indication of how ridgid it is.

 

Can't recall prices but as I'm known as a "peny pincher" can't of been too expensive.

 

Done about 20 hrs since. All seems fine. Hose clamps not needing too much extra tension after rechecking.

 

 

 

"................I purchased pre-molded elbows at various angles as bending straight sections too far caused a "kink", as an indication of how ridgid it is............".

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Thank you for your response. Very interesting.

 

How many hose connectors, per side, have you used on the radiator pipes?

 

 

Looking at your molded hoses with double elbows, if you've fitted them like that I've probably got a few more joins overall.

 

Having said that, this was the original configuration. The molded elbows saved me a couple of metal joining elbows in places and in other places I've had to add a join or two to the silicon hose.

 

As you'll appreciate, FWF's are different. Engine mounts, cowls, radiator locations, so the hose set up won't be a "one size fits all".

 

 

............ FWF's are different. Engine mounts, cowls, radiator locations, so the hose set up won't be a "one size fits all...........".

This is true even for aircraft from the same factory but a year or so apart in production date. I would doubt that any two "home built" aircraft are the same when it comes to plumbing & wiring..

 

Certain standards should still apply - minimising joins in any circuit (electrical, cooling, oil, etc) is a must if you are trying to reduce the chance of failure and for liquid circuits, keep weight down.

 

From my original 25 mm radiator pipe installation, I have managed to delete four brass joiners replacing with just one "plastic" elbow. By using pre curved hose & careful trimming for length, I have also managed to eliminate side forces on the radiator "spigots".