Neil Denmark
-
Posts
19 -
Joined
-
Last visited
Neil Denmark's Achievements
Active member (2/3)
-
I have been researching float bowl fuel leakage on my 29 year old Rotax 912A Bing 64 Carbs.
I noticed that you posted a few years ago that you had this problem. I am 90% sure I need to replace the float needle seats (I buggered them up trying to clean/resurface the donut shaped hole :-()
I have replaced float needles and floats.
These seats seem to be pressed or screwed in and not readily replaceable?
Did you manage to replace your float needle seats? Where did you source the new seats?
Not available from Rotax I think?
Maybe a BMW motorcycle parts supplier?
I hate this float system design and would change to Fuel Injection but it would cost more than my aeroplane is worth!!
Any comments would be appreciated!
-
Send your email and I'll send the info I have. I have not replaced the seats but have details on the part number and how to remove them. A mates plane I service had a leak I could not sort and Wal said may be seat corrosion that is only seen under magnification. I sent the carbs to him and fixed all good and no further issues since.
Do you use the rotax tool to set the float bracket height; they are great to use.
Cheers
Mike
-
Hi Mike
Thanks for the reply! I wonder what Wal did to fix the problem?
I have done some more research and can share my results:
I think the only way forward for me is to try and remove the float needle seat with the risk of damaging/destroying the carburetor body.
Why are secondhand Rotax carbs so hard to come by? There must be thousands tucked away in boxes all over OZ/World?
I found a supplier of the float needle seats in the USA who reckons you remove the old seat with an 8mm x 1.00 bottoming tap (which I have ordered) and heat the carb body.
In addition, I will try freezing the tap before using in the hope that this will cool the brass seat and further loosen the fitting? Fingers crossed.
The problem with sourcing from the USA is the postage costs more than the items!
I have found two Perth based BMW motorcycle shops who appear to stock the seats and viton tipped float needle valves. I am in the process of validating that these are identical to the Rotax Bing 64 types - would be great if they are and a 10th of the price!
I have not yet sourced the jig for setting float bracket height - just used calipers so far to save money!
My email address is [email protected]
cheers
Neil
-
-
Hi All, Newbie seeking help with Skyfox Gazelle
Neil Denmark replied to Neil Denmark's topic in Just Landed - Welcome
Thanks for the photo and back story! I do not have any manuals for the tail dragger version but I have asked a friend who has. I will let you know if I have any luck -
Hi All, Newbie seeking help with Skyfox Gazelle
Neil Denmark replied to Neil Denmark's topic in Just Landed - Welcome
I have a copy of the Maintenance & Repair Manual for the CA-25N Gazelle which I am happy to email you but first can you confirm you are not a scam? Do you have a Skyfox CA-22 or 25 in Thailand? How did it end up in Thailand? Cheers -
Thanks Skippy - hard to see in the photo? Went for a fly today. PTT worked fine on the pre take off call but then not working once airborne. Just working out how to remove the PTT switch - probably replace the rubber hand grip too. No idea where to get a new one? Bike shop?
-
I have two new unopened MATCO MC-5 Brake Rebuild Kits for sale. I ordered the wrong size kits so am selling these at half new retail price (Original invoice will be enclosed with package). See photos for what is in the kits. Postage at cost - message me for a postage quote. -
Thanks for the reply and info Smokey! Armed with the fact that PTT are cheap and available - I will have a go at pulling it apart 🙂
-
I suspect that the press to talk button on pilot seat control stick is failing due to intermittent transmit function. Has had a lot of use over last 28 years! Has anyone got any tips on how to inspect/replace this switch in the Gazelle?
-
Hi Guss
Yes I have been able to find all/most of the SB's and AD's on the Gazelle. Mostly from RAAUS web site which has been updated. I also have a copy of the Gazelle Maintenance and Repair Manual which is a must!
-
I am having some fuel flow issues on my Rotax 912 80hp Skyfox Gazelle. Only happens in the climb attitude so I am now suspecting the mechanical fuel pump (new installed 60hrs in 2022) is not working fully and is relying on gravity feed!
I am thinking a new mechanical fuel pump will be needed and saw a post of yours about fuel pump from europe Pierburg.
Did you end up fitting one of these to your Rotax and if so, any comments on its performance? looks a lot cheaper option that Rotax part?
Cheers Neil
-
To all Skyfox/Gazelle Owners!
I have now removed the two Fuel Non Return Valves from my Gazelle.
On draining both fuel tanks prior to removal of NRV's I could see that they were allowing fuel to backflow to the lowest level tank so clearly the "non return" function was not working.
On inspecting the simple internals I find that the flat fibre (?)disc has bent in the direction of flow - hence not sealing on backflow. The small fibre (?) sealing washer is also allowing a small amount of fuel to leak out.
Next job is to try and source replacements/parts?
The autoshop non return valves I bought on line (see earlier post) are not suitable - they need too much pressure to activ
ate flow.
-
Skyfox/Gazelle Fuel Line Non Return Valves
Neil Denmark replied to Neil Denmark's topic in Aircraft General Discussion
Thanks Skippydiesel. I am still hoping to be able to reuse the ones that are in the A/C but seeping... I will have a go at these tomorrow. I have no idea what the opening pressure is for these auto valves - there are very little specs available. Yes tanks will be low level for test. -
Skyfox/Gazelle Fuel Line Non Return Valves
Neil Denmark replied to Neil Denmark's topic in Aircraft General Discussion
Hi Guys and thanks for all your great input into what might seem like a simple topic - but is not! I have asked myself 'what is the purpose of the non - return fuel valves'. All I can come up with is that the two main (high wing) fuel tanks are "self leveling" i.e. there is no valve to select right/left tanks which is great! If you were to fly/park at a weird attitude the NRV's would stop fuel from flowing back to the lower tank (and possibly overflowing if full)? The Gazelle Maintenance Manual specifies a minimum fuel flow to the carbs of 500 ml/minute (combined total) which I will test once the new NRV's are installed. The fuel pump is located after the collector tank and provides only about 4PSI. I'll let you know how the flow test goes! These are the non return valves I was able to buy online:
-
Skyfox/Gazelle Fuel Line Non Return Valves
Neil Denmark replied to Neil Denmark's topic in Aircraft General Discussion
Thanks for your help SkippyDiesel! I have bought a couple of non return valves from an auto shop which gives me the confidence to go ahead and remove my original ones from the A/C and inspect the internals without the hazard of being grounded for weeks while I try and find replacements! -
Has any owner of a Skyfox or Gazelle got experience with changing out the fuel non return valves located between the wing tanks and collector tank behind the seat? The rubber inside the brass fittings of non return valves are known to deteriorate with age but I can't find any info on where to source replacement parts. Is there a more modern non return valve I can use? Thanks
-
That looks like a great solution! And gives you weather proof storage too. If I was not so far away...😃
