Rotax Rubber Replacement

[jackc]

Just had my Rotax 5 year rubber replacement done,  does this also include all aircraft fuel lines too?

only some of mine it appears were replaced with this hose?

Not sure IF is the correct hose?

Reason I ask is I had same type 500psi rated hose on my old ‘77 Landcruiser that runs 98 unleaded.

It lasted 18 months and ruptured near the carby, nearly causing an engine bay fire.

so I am wondering IF I should redo my Rotax dual lines?

 

[skippydiesel]

40 minutes ago, jackc said:

Just had my Rotax 5 year rubber replacement done,  does this also include all aircraft fuel lines too?

only some of mine it appears were replaced with this hose?

Not sure IF is the correct hose?

Reason I ask is I had same type 500psi rated hose on my old ‘77 Landcruiser that runs 98 unleaded.

It lasted 18 months and ruptured near the carby, nearly causing an engine bay fire.

so I am wondering IF I should redo my Rotax dual lines?

 

All engine related rubber should be replaced at the 5 year interval. This includes all fuel lines/hoses to/ from tanks.

 

Cant comment on the illustrated hose - The claimed pressure rating is way more than adequate but that has little to do with is suitability as a Rotax aircraft engine hose.

 

I use Gates products for coolant and fuel. I prefer the Fuel Injection (FI) hose to the regular carburetor grade. Both are acceptable.  The FI has a higher heat/fire rating and a lower permiability but does cost more (only a few dollars extra to do my whole system). I also prefer the FI hose clamps as they appear to give a more even 360 pressure compared with a regular worm drive hose clamp.

 

Gates products are available through your local Repco auto store.

[Thruster88]

I have had similar experience with red style hose on farm machinery, short life.  

[Kyle Communications]

I used all fuel injection hose it also has a teflon liner inside..all fuel hose was that stuff but the very expensive stuff is that orange fire sleeving..30 bucks a metre

 

[cscotthendry]

Just recently did the 5 year rubber replacement on mine too. Yes, I did the fuel lines and I used fuel injection hose on most of it. My system has several different size lines, including some 5mm stuff. I had to take what I could get locally for that.
The real PITA was the coolant hoses. I had to go through the same exercise I did when building the Nynja, finding the right diameter hoses with suitable bends.

[skippydiesel]

2 hours ago, cscotthendry said:

Just recently did the 5 year rubber replacement on mine too. Yes, I did the fuel lines and I used fuel injection hose on most of it. My system has several different size lines, including some 5mm stuff. I had to take what I could get locally for that.
The real PITA was the coolant hoses. I had to go through the same exercise I did when building the Nynja, finding the right diameter hoses with suitable bends.

Sounds similar to my Zephyr 6-8 mm, in the main . I used Holden Gemini coolant 1" hoses  with one coolant system rated plastic elbow joiner. All hoses & joiner from Gates  - no problems 

[F10]

Also did a 5 year rubber and annual on our Gazelle. 5 year kit from Floods Imports. Came with coolant oil pipes, new fuel pump, old one was fine I think, but it has rubber in it so....out went what was probably a perfectly good pump. Maybe I can give it ti a car crazy mate. Also, kit had new Bing carb rubber diaphragms. Easy to fit, just line up the little tangs on the edges of the diaphragms with carb body and chamber lid. Sounds complicated but it's not. No fuel hose as such or fire protection sheathing, so you have to supply. I don't think its specified, but fire sheathing a good thing on fuel pump hoses.

 

Location of fuel pump on reduction gearbox (Rotax 912) will mean any leak will go all over the top of a hot engine....You will hear a "whoof" and it won't be a dog. So we replaced all our fuel hosing with new, bought from "Supercheap Aerospace". I plan to carry out regular inspections of all hoses, on those weather days, when it's no point getting her out the hangar. The Gazelles had this weird transparent sheathing over all the fuel hoses in the cabin, a sort of double layer, to capture leaking fuel it seems. It was all old and cracked in places, so we got rid of it. Probably a carry over from it's VH-IOP rego days.

 

Ordered new plugs with the 5 year kit, they came with heat paste already put on the threads, nice touch but we did pay for it.           

[rgmwa]

Rotax specify one of the coolant hoses to be a pre-formed rubber hose (it has some sharper bends than the others).

Did Floods supply you that piece as well as a length of hose that you have to cut up? My kit was missing the pre-formed hose. 

 

[ClintonB]

The Bushbaby has a mix of Subaru, Ford and commodore hoses plus the Rotax one (582 model). I had to machine a joiner to complete the radiator part.

[Blueadventures]

9 hours ago, F10 said:

Also did a 5 year rubber and annual on our Gazelle. 5 year kit from Floods Imports. Came with coolant oil pipes, new fuel pump, old one was fine I think, but it has rubber in it so....out went what was probably a perfectly good pump. Maybe I can give it ti a car crazy mate. Also, kit had new Bing carb rubber diaphragms. Easy to fit, just line up the little tangs on the edges of the diaphragms with carb body and chamber lid. Sounds complicated but it's not. No fuel hose as such or fire protection sheathing, so you have to supply. I don't think its specified, but fire sheathing a good thing on fuel pump hoses.

 

Location of fuel pump on reduction gearbox (Rotax 912) will mean any leak will go all over the top of a hot engine....You will hear a "whoof" and it won't be a dog. So we replaced all our fuel hosing with new, bought from "Supercheap Aerospace". I plan to carry out regular inspections of all hoses, on those weather days, when it's no point getting her out the hangar. The Gazelles had this weird transparent sheathing over all the fuel hoses in the cabin, a sort of double layer, to capture leaking fuel it seems. It was all old and cracked in places, so we got rid of it. Probably a carry over from it's VH-IOP rego days.

 

Ordered new plugs with the 5 year kit, they came with heat paste already put on the threads, nice touch but we did pay for it.           

Hi F10  with fuel hose I use Gates carby type hose it’s USA quality, some of the super cheap stuff can fail as it’s not quite the same quality and some won’t accept any ethanol in the fuel so if the companies mix the fuel a bit it may affect the hose causing the liner to breakdown and clog some filters etc. Just posting for info and if you like look up the spec for the fuel hose you bought, brand should be on the side of the hose.  There are some other good quality fuel hoses mentioned in the Savannah threads.  Cheers and enjoy the Gazelle.

Also there is a full copy of the Gazelle maintenance manual on this site that is worth downloading.

Edited May 7, 2021 by Blueadventures

[John Robert]

I thought that it was compulsory to use a fire sleeve with all fuel & oil lines inside the cowls. Compulsory or not I would not have a naked fuel or oil line around a hot engine without a fire sleeve. My first rubber change from new in 2011 had me tugging & twisting to remove a Gates hose fitted as an original. It still felt soft & pliable & I was wondering if it was really necessary. Changed my opinion when the hose broke & I examined the cords. A fuel line should not break, I hung it on the hangar wall as a reminder & when I did the next rubber change looked at it again. At 10 years old the hose had surface cracks & it was possible to break pieces off . Maybe it was a faulty batch, its still on the hangar wall ready to show anyone who is reluctant to do the 5 year rubber change. Some Flight Design owners in the US had problems with rubber sharves in the Bing float chambers. This was found to be only when they had fitted fuel injection hoses. The reasoning was that the injection hose is much harder & quite difficult to fit . Twisting & pushing was deemed to be the cause of the slivers of rubber finding its way into the carb & causing engine problems often intermittent & difficult to diagnose. It is not necessary to use a high pressure hose designed for fuel injection on a Bing carb that cannot handle  above 5PSI. There could also be an argument that the low pressure hose will compress more easily to give a better seal with lower tension on the fitting. The Rotax fuel pump at one time was not included in the rubber change. It is now & if you have noticed how flimsy the diaphram is for the Bing carbs there is also a similar one in the fuel pump. A shame they do not fit a serviceable pump so the diaphragm can be replaced.

A friend was considering fitting the Teflon hoses which do not have a timed life. They look fantastic,I was given this link but have no experience with this company  <http://aircraftspecialty.com/RV12Fuelkit.html>.

It is  good to have these discussions about critical maintenance there is so much to learn on some of the websites.

 

[skippydiesel]

12 hours ago, F10 said:

Also did a 5 year rubber and annual on our Gazelle. 5 year kit from Floods Imports. Came with coolant oil pipes, new fuel pump, old one was fine I think, but it has rubber in it so....out went what was probably a perfectly good pump. Maybe I can give it ti a car crazy mate. Also, kit had new Bing carb rubber diaphragms. Easy to fit, just line up the little tangs on the edges of the diaphragms with carb body and chamber lid. Sounds complicated but it's not. No fuel hose as such or fire protection sheathing, so you have to supply. I don't think its specified, but fire sheathing a good thing on fuel pump hoses.

 

Location of fuel pump on reduction gearbox (Rotax 912) will mean any leak will go all over the top of a hot engine....You will hear a "whoof" and it won't be a dog. So we replaced all our fuel hosing with new, bought from "Supercheap Aerospace". I plan to carry out regular inspections of all hoses, on those weather days, when it's no point getting her out the hangar. The Gazelles had this weird transparent sheathing over all the fuel hoses in the cabin, a sort of double layer, to capture leaking fuel it seems. It was all old and cracked in places, so we got rid of it. Probably a carry over from it's VH-IOP rego days.

 

Ordered new plugs with the 5 year kit, they came with heat paste already put on the threads, nice touch but we did pay for it.           

Maaate! Buying, unknown quality, hoses from SCA is a completely unnecessary risk and no saving in $$$

 

I have used Gates fuel & coolant hoses, purchased through Repco, for 12  years or so. You can look up (Google) the specifications on all Gates products - try thet with SCA

 

I personally use fuel injected rated hose, as it gives lower permiability, higher heat/fire resistance and has a working pressure that a Rotax fuel system will never even come close too. Cost per m is only slightly more than carburetor hose (remember Repco sales people can negotiate on the price so do so)

 

 After 5 years, my hoses are in such good condition, they get re used on my land based machinery.

 

I used automotive insulating sleeve on my over engine fuel lines - mainly to reduce (sadly not eliminate) fuel vaporisation.

 

Don't know what fuel pump you have fitted but if its the latest generation (which it should be), it has a fuel/oil bleed point, that you are supposed to fit a hose to, to exit any leaks overboard, well away from the hot engine/exhaust.

[skippydiesel]

2 hours ago, John Robert said:

I thought that it was compulsory to use a fire sleeve with all fuel & oil lines inside the cowls. Compulsory or not I would not have a naked fuel or oil line around a hot engine without a fire sleeve. My first rubber change from new in 2011 had me tugging & twisting to remove a Gates hose fitted as an original. It still felt soft & pliable & I was wondering if it was really necessary. Changed my opinion when the hose broke & I examined the cords. A fuel line should not break, I hung it on the hangar wall as a reminder & when I did the next rubber change looked at it again. At 10 years old the hose had surface cracks & it was possible to break pieces off . Maybe it was a faulty batch, its still on the hangar wall ready to show anyone who is reluctant to do the 5 year rubber change. Some Flight Design owners in the US had problems with rubber sharves in the Bing float chambers. This was found to be only when they had fitted fuel injection hoses. The reasoning was that the injection hose is much harder & quite difficult to fit . Twisting & pushing was deemed to be the cause of the slivers of rubber finding its way into the carb & causing engine problems often intermittent & difficult to diagnose. It is not necessary to use a high pressure hose designed for fuel injection on a Bing carb that cannot handle  above 5PSI. There could also be an argument that the low pressure hose will compress more easily to give a better seal with lower tension on the fitting. The Rotax fuel pump at one time was not included in the rubber change. It is now & if you have noticed how flimsy the diaphram is for the Bing carbs there is also a similar one in the fuel pump. A shame they do not fit a serviceable pump so the diaphragm can be replaced.

A friend was considering fitting the Teflon hoses which do not have a timed life. They look fantastic,I was given this link but have no experience with this company  <http://aircraftspecialty.com/RV12Fuelkit.html>.

It is  good to have these discussions about critical maintenance there is so much to learn on some of the websites.

 

I have always used Gates fuel injection hose - never even had a hint of a problem (see above post to F10). I think it more likely that:

1.  People fail to blow out (HP air) the hoses befor fitting, thus removing any "swarf" from the cutting to length process
2. Do not use proper hose cutters (cheap as), leading to a lot of swarf generation
3. If fitting is the problem, you have described, they are trying to fit the wrong ID hose - no problemo IF  you get the right hose for the job
4.  Like you, have kept the hose in service, well past the Rotax recommended 5 year change interval.

 

Picky, I apologise, but the Max fuel  pressure is closer to 6 psi

 

"A friend was considering fitting the Teflon hoses which do not have a timed life."

I dont get it. Rotax make a recommendation based on their experience & rigorously conducted trials. Your mate goes out and pays "an arm and a leg" for a product, not recognised by Rotax, when he could probably do 50/5 years of Gates fuel hose for a similar price  and stay within Rotax recommendations - Oh I forget "They look fantastic" 

 

[John Robert]

Skippy, you misquoted me. I hope you understand technical instructions better than your understanding of what I wrote. I said "I hung the piece of hose on my hangar wall & left it until the next rubber change at which time I was able to break pieces off it." I have always changed my rubber hoses  at the 5 years recommended time. "My friend was considering" but has not done the Rubber change yet.  Rotax actually use some teflon hoses, cost is maybe what prevents them from having all teflon. If I consider the fact that often the fire sleeve is  damaged  after the removal of the old hose, & it is much more expensive than the hose. Add the cost of 4 new clamps for the hose & sleeve per length, I dont use Jubilee clips just single ear stepless  SS. hose clips. There is a good argument for the teflon kit which is recommended by Van's for the RV 12. If you check on the specs of Teflon hose you may find that there will be zero fuel vaporisation through the hose. Often if something looks fantastic it usually is. I have almost justified the cost of the kit to myself for the next change.

[skippydiesel]

56 minutes ago, John Robert said:

Skippy, you misquoted me. I hope you understand technical instructions better than your understanding of what I wrote. I said "I hung the piece of hose on my hangar wall & left it until the next rubber change at which time I was able to break pieces off it." I have always changed my rubber hoses  at the 5 years recommended time. "My friend was considering" but has not done the Rubber change yet.  Rotax actually use some teflon hoses, cost is maybe what prevents them from having all teflon. If I consider the fact that often the fire sleeve is  damaged  after the removal of the old hose, & it is much more expensive than the hose. Add the cost of 4 new clamps for the hose & sleeve per length, I dont use Jubilee clips just single ear stepless  SS. hose clips. There is a good argument for the teflon kit which is recommended by Van's for the RV 12. If you check on the specs of Teflon hose you may find that there will be zero fuel vaporisation through the hose. Often if something looks fantastic it usually is. I have almost justified the cost of the kit to myself for the next change.

Maaaate! - I may have misunderstood a little (my apologizes) but at the end of the day, when it concerns the engine,  Rotax is the authority you should be listening to, not the airframe manufacturer. Remember Rotax 91 engines, motivate a very wide range of aircraft (certified, LSA  & experimental) - the engine does not change and neither should your source of information.

 

On the clamps/clips - use whatever you prefer ,the main thing is that the clamps are the right size for the job, provide a 360 even pressure, do not damage the hose and are not done up to tight - clamps are primarily for security, not for preventing leaks. Personally I use fuel injection clamps.

 

 

[jackc]

I am about to redo my 5 year rubber replacement after the LAME used fuel line that  is junk and has started to crack near the hose clamps after 3 months..  He left the bowl clip loose and drain tube hanging.

..

 

This red fuel line (below) lasted 18 months on my 77 Petrol Landcruiser, then ruptures spraying fuel over the engine.

 

 

 

 

 

[John Robert]

This link will resolve any disagreement about Rotax approval of Teflon hoses.<https://legacy.rotaxowner.com/si_tb_info/serviceinfo/si-912-022.pdf>

As in rubber hoses there are different qualities in Teflon. I have read that non conductive hoses are the best. I would spend some time researching specifications before I fitted them. They cannot be fitted to the standard barbed fittings used for rubber hoses. So that requires replacement of all fittings. The kit cost is about Au $2000  + shipping for all oil & fuel hoses with fire sleeves. The supplier for Vans Aircraft tests each hose after assembly. Seems like a lot of $ but it would reduce the labour on the  first install with no other costs after that. The value of the  additional safety with the fire sleeves would depend on the individual.  Personally I would not want to fly without the fire sleeve especially as the CT does not have a steel firewall.

[skippydiesel]

3 hours ago, John Robert said:

This link will resolve any disagreement about Rotax approval of Teflon hoses.<https://legacy.rotaxowner.com/si_tb_info/serviceinfo/si-912-022.pdf>

As in rubber hoses there are different qualities in Teflon. I have read that non conductive hoses are the best. I would spend some time researching specifications before I fitted them. They cannot be fitted to the standard barbed fittings used for rubber hoses. So that requires replacement of all fittings. The kit cost is about Au $2000  + shipping for all oil & fuel hoses with fire sleeves. The supplier for Vans Aircraft tests each hose after assembly. Seems like a lot of $ but it would reduce the labour on the  first install with no other costs after that. The value of the  additional safety with the fire sleeves would depend on the individual.  Personally I would not want to fly without the fire sleeve especially as the CT does not have a steel firewall.

Everyone assess risk differently - use good quality hose every 5 years, look after your electrical security and it is most unlikely you will experience a fire as a result of a spit hose or an arcing wire. I have never heard of this in a well maintained aircraft, & I suggest its rare across  all sport aircraft. If it improves your feeling of security - go with it but doubt the cost effectiveness of the (Teflon).

 

This is a debate that has no right/ wrong, very similar to the ballistic parachute 

[F10]

On 07/05/2021 at 5:15 PM, rgmwa said:

"Did Floods supply you that piece as well as a length of hose that you have to cut up? My kit was missing the pre-formed hose." 

 

No, the Gazelle has coolant rad setup unique to it, as do Kitfox, Eurofox, all slightly different rad positioning. So we had to rummage through the hose bends bin at "Supercheap Aerospace" to get the right bend size and then cut the pipe length as required. Some say, SCA fuel pipe is dodgy, well its pretty thick fuel pipe with a good grippy softish feel, I have used it before, it's tough, simple, handles Mogas just fine. Lasts forever in most old Holden of Falcon wagons...Like I said, I plan to inspect the engine on a regular basis, the Gazelle is good in that the cowling is just two pieces, top and bottom, easy to remove. Take them off and the whole engine is exposed. Good advice I was given is to choose a fuel line or coolant line and carefully follow it over the engine beginning to end. Then choose and follow another. Don't try look over the whole engine as such, its too much information to take in one hit, so you may miss something. 

[F10]

16 hours ago, jackc said:

I am about to redo my 5 year rubber replacement after the LAME used fuel line that  is junk and has started to crack near the hose clamps after 3 months..  He left the bowl clip loose and drain tube hanging.

..

 

This red fuel line (below) lasted 18 months on my 77 Petrol Landcruiser, then ruptures spraying fuel over the engine.

 

 

 

 

 

Jackc, wow, LAME leaving float bowls loose (I see the non vertical clip in the top pic), is quite serious....I’ve always thought it a bit ironic how some people in GA frown at RAA owners doing their own maintenance, because you hear of a lot of LAME horror stories. Yes, no doubt horror stories on both sides....but a mate recently had his Eurofox serviced ($$$$) flying back, oil temp was higher than normal, on landing, found the oil rad flap had not been re-connected. Previous owner of my Gazelle sold it because it was costing too much to maintain, I saw one receipt. Total was for around $3000, of that only $60 was for parts, the rest was labour. Now not saying that wasn’t legit...but it’s great to be able to do a lot of your own maintenance!

[jackc]

That was just the start of it......bent undercarriage axle,  unequal undercarriage leg fitted for a ground loop repair.......the list goes on.

No problem for me, like everything in my life I will just fix it all and I guarantee any LAME won’t find a fault, anywhere.

 

[skippydiesel]

11 hours ago, F10 said:

No, the Gazelle has coolant rad setup unique to it, as do Kitfox, Eurofox, all slightly different rad positioning. So we had to rummage through the hose bends bin at "Supercheap Aerospace" to get the right bend size and then cut the pipe length as required. Some say, SCA fuel pipe is dodgy, well its pretty thick fuel pipe with a good grippy softish feel, I have used it before, it's tough, simple, handles Mogas just fine. Lasts forever in most old Holden of Falcon wagons...Like I said, I plan to inspect the engine on a regular basis, the Gazelle is good in that the cowling is just two pieces, top and bottom, easy to remove. Take them off and the whole engine is exposed. Good advice I was given is to choose a fuel line or coolant line and carefully follow it over the engine beginning to end. Then choose and follow another. Don't try look over the whole engine as such, its too much information to take in one hit, so you may miss something. 

So you are able to get the same level of specification information for a SCA supplied hose as you are for a Gates (from Repco) ?????

 

I confess, I misused the loose float bowl (focused in on the hose) so well done F10 - this is definitely the sort of avoidable error that may cause a fire -  far more so than correctly fitted fuel hoses.

[onetrack]

I would never use anything from Supercheap on an aircraft, because Supercheap focus 100% on the cheapest products they can find, to produce the maximum profit.

There's a lot of rubbishy rubber products that come out of Malaysia, Indonesia and China, that Supercheap mostly specialise in. If you want quality in rubber components, you use Gates products, and Gates Green Stripe where possible.

Anything designed for Marine use normally has superior quality in construction style and materials.

 

Rubber components are the weak link in every engine system. Anything you can do to reduce the amount of rubber in an aircraft is going to appreciably increase that aircrafts safety level.

If it was my choice, and my aircraft (and I don't own an aircraft), I'd be choosing to eliminate as many rubber/rubberised hoses, as I possibly could. 

 

Any hose that is red or yellow coloured has a short life, due to more rapid and more intense UV absorption. Green-coloured hose has the longest life, due to minimal UV absorption.

[biggles]

Those open slotted hose clamps sure do damage hoses, particularly if overtightened. These were apparently on a motor vehicle, but have no place on an aircraft engine..... Bob 

[jackc]

1 hour ago, biggles said:

Those open slotted hose clamps sure do damage hoses, particularly if overtightened. These were apparently on a motor vehicle, but have no place on an aircraft engine..... Bob 

Al my red hose and worm drive clamps are going in the bin......and I have lots of fire sleeving to do as well.......