FlyingMonkey Posted August 11, 2016 Report Share Posted August 11, 2016 What freaks me out is that I have to turn off the engine to shut the fuel valve, meaning that that leak would continue for about 2 minutes (how long it took to stop on the ground). If I could have shut the fuel off and ran the engine until it stopped, I possibly could have starved a fire. I'll take a stopped engine over a fire any day of the week, even (especially!) in flight. Link to comment Share on other sites More sharing options...
FlyRatz Posted August 16, 2016 Report Share Posted August 16, 2016 Once I had the exact same issue with one of our planes. I do not remember which one it was since it is 2 years ago or so. You remembered me to seal the holes at all of our carb bowls at the next inspection. Thank you Link to comment Share on other sites More sharing options...
Johnny Posted September 26, 2016 Report Share Posted September 26, 2016 The pin issue may be rare, but not to me ... have had it happen twice! At the time of the first incident, a couple years ago, I guess it was pretty unusual ... Roger had never heard of it! Link to comment Share on other sites More sharing options...
Roger Lee Posted September 26, 2016 Report Share Posted September 26, 2016 It's rare, but we just had a case. They are easy to fix. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted September 27, 2016 Report Share Posted September 27, 2016 So that is at least five cases just in this thread. I'm slightly surprised there has not been an engine fire related to this. Link to comment Share on other sites More sharing options...
opticsguy Posted October 3, 2016 Author Report Share Posted October 3, 2016 I finally got back to Wisconsin and noticed fuel in the drip tray on the opposite side. Sure enough, both pins were leaking. I plugged them with expoxy, did a high speed run, and no leaks. These two had been leaking for almost 3 years and my mechanic at the time didn't find them. To add insult to injury, my D100 backlight went out, so I couldn't fly. So far, I've got 3 out of 4 pins leaking at 9 years, and a catastrophic failure at 10. I would think the FAA would be interested in this. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted October 3, 2016 Report Share Posted October 3, 2016 So far, I've got 3 out of 4 pins leaking at 9 years, and a catastrophic failure at 10. I would think the FAA would be interested in this. I'd rather get Rotax involved than the FAA. Little good usually comes from federal intervention. Link to comment Share on other sites More sharing options...
Roger Lee Posted October 3, 2016 Report Share Posted October 3, 2016 Rotax and the FAA would say are you inspecting your carbs every 200 hrs and have you had them overhauled in 9 years. Many parts have life expectancies and not all are 2000 hr. TBO's. These are very easy to foix. Just remove the loose pin, clean the end and hole with lacquer thinner and use Loctite 648 and press them back in place. This is one reason you are supposed to have drip trays. Anything on the carb that has fuel could leak under the right circumstances. Link to comment Share on other sites More sharing options...
opticsguy Posted October 3, 2016 Author Report Share Posted October 3, 2016 If the pins are supposed to be glued in, then Rotax should issue a SA on that. If carb bowls aren't inteded to last more than 5 years, they should be a replacement item so many hours or years. I filled out a form with Rotax and have heard nothing. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted October 4, 2016 Report Share Posted October 4, 2016 Rotax and the FAA would say are you inspecting your carbs every 200 hrs and have you had them overhauled in 9 years. Many parts have life expectancies and not all are 2000 hr. TBO's. These are very easy to foix. Just remove the loose pin, clean the end and hole with lacquer thinner and use Loctite 648 and press them back in place. This is one reason you are supposed to have drip trays. Anything on the carb that has fuel could leak under the right circumstances. The problem is not the difficulty in repair, it's the volume of the leak. My drip tray overflowed and spilled gasoline all over the engine, I'd bet a quart or two. I don't believe the carb overhaul specifically mentions checking the pins, or any spec for doing do. My carbs have less than nine years on them anyway. Link to comment Share on other sites More sharing options...
opticsguy Posted October 8, 2016 Author Report Share Posted October 8, 2016 Note my first post. 2 gph leaking out of one hole. It took a good 5 minutes after the fuel valve was shut for it to stop. That's long enough to fry everything. Link to comment Share on other sites More sharing options...
Buckaroo Posted December 13, 2016 Report Share Posted December 13, 2016 This topic caught my attention! I think I understand what going on with the pins and them vibrating loose and dislodging out of there mounts leaving a hole in the bottom of the carb! I need to address this issue. Can I dab epoxy on my finger and squeeze it up into the hole while the carbs are in position? Would squeezing locktight 648 from the tube be better fighting gravity and all? Is there room to do this with carbs in position? Thanks folks! Link to comment Share on other sites More sharing options...
Roger Lee Posted December 13, 2016 Report Share Posted December 13, 2016 This is rare and is usually caused by people rough handling the carb bowls and or not doing carb syncs and causing excessive vibration, warming up at too low an rpm, anything that causes excessive vibration. You can put a drop of epoxy on the underside of the pin hole, but the carb will overflow and just come out the vent. the result for masny will be the same IF you don't have the Rotax aluminum airbox where the vent tubes go back into the airbox. Putting epoxy on the bottom is more or less a feel good thing. If a pin ever did come out just put it back in place with some Loctite 648. Link to comment Share on other sites More sharing options...
Buckaroo Posted December 13, 2016 Report Share Posted December 13, 2016 Thanks I can vision exactly what you're talking about from experience on my BMW motorcycle carbs. You worked on my ride over the years and I'm sure she was handled skillfully! Not going to worry about it! Thanks Dave Link to comment Share on other sites More sharing options...
FlyingMonkey Posted December 13, 2016 Report Share Posted December 13, 2016 All due respect to Roger, whose opinion I surely respect on this stuff... The failure mode in my case (and at least a couple others I'm aware of) was that the pin worked loose, but stayed in place. The floats continued to work normally. In that case, epoxy on the holes would have stopped a leak altogether or at least slowed it to a drip. No fuel would have come out the vents because the floats were working. In my opinion, the epoxy can never hurt and in what seems like about half the cases it could make a difference between a huge leak and a tiny leak or none at all. It's cheap insurance. My understanding is that the new float bowls have blind drilled holes, which if true sure seems like a tacit admission by Bing/Rotax of an issue with the original design... Link to comment Share on other sites More sharing options...
Roger Lee Posted December 13, 2016 Report Share Posted December 13, 2016 Hi Andy, I never take offence to any debate or difference of opinion. I'm always a happy camper. My only concern is that someone doesn't think this is a cure all solution. If the fuel can't come out one place it will find another. One way to help combat this is if you take the bowls off tap the pins down and in the rare case this might happen it may prevent the pin from ever coming out. p.s. Don't bend that darn pin. Link to comment Share on other sites More sharing options...
WmInce Posted December 13, 2016 Report Share Posted December 13, 2016 According to Lockwood Aviation, those pins become loose from improper handling. Link to comment Share on other sites More sharing options...
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