Rich Posted August 7, 2015 Report Share Posted August 7, 2015 I have researched the archives on carbs. I had started the topic awhile back, but would like to know definitely if the carbs MUST be taken apart and inspected at the 200 hr. mark? I've reached that number of hours and would like to know if the inspection is suggested or mandatory? What if I chose not to at this time? I hate to have them taken apart when they are working perfictly. Link to comment Share on other sites More sharing options...
gbigs Posted August 7, 2015 Report Share Posted August 7, 2015 Here is a summary of all maintenance intervals for Rotax: http://www.lightaircraftassociation.co.uk/engineering/Maintenance/Rotax%20Service%20Interval%20Guide%20%20April%202011.pdf Here is what's required every 200 hrs or 2 years: 100hr service plus: Differential (leakdown) compression test, check carburetor rubber sockets (please note that some carburetor rubber sockets are subject to a 50hr inspection.) Strip and inspect carburetors , check spark plug caps and replace spark plugs. Note. All rubber components in the carbs must be replaced at the 5-year interval. Link to comment Share on other sites More sharing options...
Roger Lee Posted August 7, 2015 Report Share Posted August 7, 2015 This will be a hot topic not because carbs fall apart, but because of attitudes towards maint. and regs. and just like discussions on politics and religion will differ. Two schools of thought here. You get to decide on what side of the fence to fall. Some will follow the rule to the letter no matter what. Others will say wait until it's on the verge of not working or fails. (I hate the term don't fix it if it ain't broke because it's used as a cop out too often and many wouldn't know if it was going to break if it hit them between the eyes. ) This answer depends on which 200 hr. inspection we are talking about. The first 200 hr. TTSN or 800 hrs. TTSN? First it's on the Rotax check list for the 200 hr. This would require the removal and disassembly of the carb. If you disassemble you may need to start replacing "O" rings that you disturb. I don't really know of anyone who has found anything unless you have a dirty bowl which doesn't need a carb disassembly to find. Of all the maintenance items I think needs to be done this isn't one of them. This is my personal opinion and someone elses may differ. The other school of thought is no one ever has an issue at 200 hrs. and so long as the engine runs well, the carb bowls are clean and they always sync then I believe you can leave them alone. Many people wait until the 5 year rubber replacement and many wait until 1000 hrs. up to 8 years. So you see this is kind of all over the map with many different thoughts. I rebuild a lot of carbs sent from all over the country and most have around 8 years or 800-1000+ hrs on them. What I normally find are cracked "O" rings from age, a few needles worn from vibration due to poor sync habits, water deposits in the bowls from the guys in high humidity or that have been left in the rain and just downright dirty carbs internally from never bothering to ever look or maintain their engine. (Don't fix it if it ain't broke attitude) Bottom line is it's your call. By the letter or by common sense. Link to comment Share on other sites More sharing options...
Rich Posted August 7, 2015 Author Report Share Posted August 7, 2015 Roger Lee, on 07 Aug 2015 - 12:32 PM, said: This will be a hot topic not because carbs fall apart, but because of attitudes towards maint. and regs. and just like discussions on politics and religion will differ. Two schools of thought here. You get to decide on what side of the fence to fall. Some will follow the rule to the letter no matter what. Others will say wait until it's on the verge of not working or fails. (I hate the term don't fix it if it ain't broke because it's used as a cop out too often and many wouldn't know if it was going to break if it hit them between the eyes. ) This answer depends on which 200 hr. inspection we are talking about. The first 200 hr. TTSN or 800 hrs. TTSN? First it's on the Rotax check list for the 200 hr. This would require the removal and disassembly of the carb. If you disassemble you may need to start replacing "O" rings that you disturb. I don't really know of anyone who has found anything unless you have a dirty bowl which doesn't need a carb disassembly to find. Of all the maintenance items I think needs to be done this isn't one of them. This is my personal opinion and someone elses may differ. The other school of thought is no one ever has an issue at 200 hrs. and so long as the engine runs well, the carb bowls are clean and they always sync then I believe you can leave them alone. Many people wait until the 5 year rubber replacement and many wait until 1000 hrs. up to 8 years. So you see this is kind of all over the map with many different thoughts. I rebuild a lot of carbs sent from all over the country and most have around 8 years or 800-1000+ hrs on them. What I normally find are cracked "O" rings from age, a few needles worn from vibration due to poor sync habits, water deposits in the bowls from the guys in high humidity or that have been left in the rain and just downright dirty carbs internally from never bothering to ever look or maintain their engine. (Don't fix it if it ain't broke attitude) Bottom line is it's your call. By the letter or by common sense. Roger, In my case it's 200 since new. Carb bowls are clean and have remained clean since the debris was found when the engine was new. Link to comment Share on other sites More sharing options...
Roger Lee Posted August 7, 2015 Report Share Posted August 7, 2015 Personally from years of experience and if you have had no issues to address then I'm sure they are good to leave alone, but that call is between you and your mechanic. Link to comment Share on other sites More sharing options...
Anticept Posted August 7, 2015 Report Share Posted August 7, 2015 Personally, I don't replace the o-rings or gaskets unless there's a sign of degradation, simply because of the high utilization of our aircraft. For private owners that don't log 200 hours in a year, then I definitely replace them. Since we have such high utilization, and we're not putting much pressure on the o-rings at all (god, some people put this stuff together WAY too tight), I end up keeping them lubricated with a light coat of lithium grease and they stay nice and soft. I do prefer to do the 200 hour inspections because I'm almost always replacing an o-ring (the idle mixture screws go through o-rings like crazy for some reason), or emptying a few specs of debris from the carb bowl. Disclaimer: The logic that I use is anything uses o-rings but isn't frequently inspected, then the o-rings get replaced. No telling how old the ring is, or when I will next see it, so it's good practice there. For these carbs, since it's so frequent, and I keep a coat of grease on them, I'm not worried. Link to comment Share on other sites More sharing options...
gbigs Posted August 7, 2015 Report Share Posted August 7, 2015 Did you see the NTSB report on Harrison Ford's crash? It was due to a carburetor...the engine was flooded and failed... http://www.usatoday.com/story/life/2015/08/06/ntsb-reports-cause-harrison-ford-plane-crash/31246511/ Link to comment Share on other sites More sharing options...
Rich Posted August 7, 2015 Author Report Share Posted August 7, 2015 Thank you for the replies. Rich Link to comment Share on other sites More sharing options...
FlyingMonkey Posted August 7, 2015 Report Share Posted August 7, 2015 Did you see the NTSB report on Harrison Ford's crash? It was due to a carburetor...the engine was flooded and failed... http://www.usatoday.com/story/life/2015/08/06/ntsb-reports-cause-harrison-ford-plane-crash/31246511/ A carb for which there was no service documentation, which had been overhauled along with the engine within the last 150hrs. The problem was an unseated jet. Hardly something that could be planned for without any documentation. Link to comment Share on other sites More sharing options...
Roger Lee Posted August 7, 2015 Report Share Posted August 7, 2015 The things with our carbs is if there is an issue you'll know it way before the 200 hr. mark rolls around. Are carbs are sensitive to any kind of issue. Ford had 1 carb we have two and the plane may run rough, but it will still fly or land. Link to comment Share on other sites More sharing options...
sandpiper Posted August 11, 2015 Report Share Posted August 11, 2015 Personally from years of experience and if you have had no issues to address then I'm sure they are good to leave alone, but that call is between you and your mechanic. My mechanic can be very unreasonable. Link to comment Share on other sites More sharing options...
Doug Hereford Posted August 13, 2015 Report Share Posted August 13, 2015 Rich, The short answer to your question is No. There is no legally required 200hr. Carburetor inspection on the aircraft. The rest of the legal answer is not as clear-cut in my opinion. SLSA aircraft have only ONE required inspection. It is a "Condition" inspection. Legally, this inspection is required on an annual basis, or a 100 hr. TIS basis (depending on operation)........period (ref. 91.327 and operating limitations). Where things become murky is that this "Condition" inspection has to be of the scope and detail necessary for the inspector to certify the entire AIRCRAFT in a condition for safe operation. The special carburetor inspection requirement leaves the inspector out on a limb, if not done at each Condition inspection interval (Annual/100hr.). Because it is an "inspection", one could argue that performing it is necessary to confirm that the Aircraft is safe, and therefore required at every Condition inspection interval. A decision needs to be forced upon FD. Either include the carburetor inspection in the annual/100 hr. Condition inspection procedures, or remove it completely. If FD feels that this inspection is actually necessary for safety, but doesn't feel that the frequency of the inspection needs to be every year, then they must issue a Safety Directive to legally mandate this special inspection. I would echo this position for the "Wing" special inspection, and any other special inspections on the aircraft. Doug Hereford PS. My response was aimed at your "legal" question. My personal opinion on the matter from a practical point may be much different. Link to comment Share on other sites More sharing options...
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