fevlok@mmhs.co.za Posted December 12, 2014 Author Report Share Posted December 12, 2014 Just some interesting feed back I was very busy lately and what a disapointment when after about 5 houers flying the CT it start to run ruff and loose power on climb out !!! Only today we could test her after putting spare carbs and manifuls on On the test : again power loss !!!! Whe replase the fuel pump (had a spaire )((a clue : if you shake the old pump something ratle inside)) , not so confident we got in the plaine and after an hour of climbing and take offs no problem !! , but i am scare to even say it Looking back this only happen on full power climb some time a litle bit on cruise what through us off also was the left side of the enjin the sparkplugs was burned white and right side wet ? /Egt lt side and right side differ with 200 on full power ? May be it was a combination of things but this time I am convince it was the fuel pump My wife need some hours so gues i will fly hopefully more and keep you posted Kiewiet Link to comment Share on other sites More sharing options...
cdarza Posted March 7, 2015 Report Share Posted March 7, 2015 Was on a flight and had a vibration/sight power loss (this was after about an hours flight) I had been doing some steep turns etc so i thought of a few things that might have caused this - the sloshing around perhaps moved some water in the tanks, the balance tube got out of the center or some dirt in the fuel. ??? It was quite a scare as the vibration was at around 4300-4500 rpm and i could not get full power. I stayed at 4000 rpm (on way to land) and after a few minutes i again advanced the throttle. It vibrated a little then full power came in. I tried to replicate this on the ground with multiple run ups that resulted in no issue. Next flight went well - no issues. Flight after that seemed to have some slight vibration at around 4800 rpm (but only after about an hours flight) This last flight went well on takeoff but on crosswind the power dropped 200rpm. Went back to land but on downwind i played with the rpm range. I was getting vibrations at at varying rpms in the 4500-5000 range intermittently (it was not vibrating at only one specific rpm setting) Landed and did run ups again in the ground. At times the full range would be normal and at times i would again get slight to heavy vibration around 4500 to 4800. My normal static full power is 5000 rpm. I would get this but then have a 200 rpm drop.... that would seem to 'clear' and go back to 5000rpm. Plane is now grounded until i resolve this issue. My first thought is to remove and clean/rebuild the carbs... 2006CTSW 575hours Would appreciate thoughts on this. Christopher Link to comment Share on other sites More sharing options...
FastEddieB Posted March 8, 2015 Report Share Posted March 8, 2015 First thing is check the float bowls and jets. See if there's any crud in there. Link to comment Share on other sites More sharing options...
Tom Baker Posted March 8, 2015 Report Share Posted March 8, 2015 After that reach in the back of the carb and see if the slide is sticking. Link to comment Share on other sites More sharing options...
Tip Posted March 8, 2015 Report Share Posted March 8, 2015 Sounds like the vent tube between the two carbs. Make sure the tube is on each carb and the holes are inside the air filter box. Link to comment Share on other sites More sharing options...
Jacques Posted March 8, 2015 Report Share Posted March 8, 2015 all of the above but.. TIP... the tubes you're talking about are the vent tubes. The balance tube is the 'big' one between the carbs intake. Link to comment Share on other sites More sharing options...
Roger Lee Posted March 8, 2015 Report Share Posted March 8, 2015 I agree. Check the carb bowls first then pop the tops of the carbs off to see if the pistons are dirty and not moving freely. You move dirt around in the bowls and it gets sucked up as the fuel sloshes. The fuel doesn't slosh on the ground so the problem is not usually repeatable. Link to comment Share on other sites More sharing options...
Tom Baker Posted March 8, 2015 Report Share Posted March 8, 2015 I agree. Check the carb bowls first then pop the tops of the carbs off to see if the pistons are dirty and not moving freely. You move dirt around in the bowls and it gets sucked up as the fuel sloshes. The fuel doesn't slosh on the ground so the problem is not usually repeatable. With the CTSW I find it easier to take the duct tube off the back of the carb and reach in to check the slide. Link to comment Share on other sites More sharing options...
Roger Lee Posted March 8, 2015 Report Share Posted March 8, 2015 How do you look inside the piston guide rod area and piston skirt to check for dirt in a 360 degree area if all you do is pull the intake tube off? The top should come off. Without disconnecting the the throttle or choke cable just remove the throttle arm and choke arm with the 11mm nut. You will not affect the carb sync this way. Then unscrew the top two screws on the carb top and the whole carb top body and piston come out. I have seen a few with really old fuel that has dried cause the piston to hang up slightly and black sooty dirt cause the piston guide in the top of the carb to do the same. This job is a quick and easy process. Link to comment Share on other sites More sharing options...
Tom Baker Posted March 9, 2015 Report Share Posted March 9, 2015 How do you look inside the piston guide rod area and piston skirt to check for dirt in a 360 degree area if all you do is pull the intake tube off? The top should come off. Without disconnecting the the throttle or choke cable just remove the throttle arm and choke arm with the 11mm nut. You will not affect the carb sync this way. Then unscrew the top two screws on the carb top and the whole carb top body and piston come out. I have seen a few with really old fuel that has dried cause the piston to hang up slightly and black sooty dirt cause the piston guide in the top of the carb to do the same. This job is a quick and easy process. Roger, I'm talking about a quick check for trouble shooting. If it is gummed up enough to cause the engine to run rough you will be able to feel it by lifting and letting the piston fall. If you don't feel any binding then it is probably not the problem, if you do feel binding then pull it for cleaning. The two I have seen there was no doubt about whether it was binding or not. Link to comment Share on other sites More sharing options...
C ICEY Posted March 9, 2015 Report Share Posted March 9, 2015 similar enigmatic power loss/roughness once upon a time, that manifested in power loss but only at full throttle. quite disconcerting around these parts... checked carbs, plugs, plug boots, compensation tubes, fuel lines and filters, fuel pump, and ignition modules..... yikes. turned out to be a slight kink on one throttle cable making the full throttle miss one stops very slightly, putting it a bit out of balance. In the past I used my carbs for quite a few balancing demonstrations at a nearby maintenance facility, and over time, with all the adjustments and hands , the cable lost some of its function. a crisp, fresh new cable got the fuel levers moving in unison, and I got a new appreciation for thorough troubleshooting. Link to comment Share on other sites More sharing options...
FredG Posted March 9, 2015 Report Share Posted March 9, 2015 C ICEY - thanks for the update. Makes me wonder of some of the difference in EGT some pilots report is due do inconsistent throttle cable action. Link to comment Share on other sites More sharing options...
Roger Lee Posted March 9, 2015 Report Share Posted March 9, 2015 EGT'S are usually affected by out of sync carbs (doesn't take much), plugs, old EGT probes, throttle cables and internal carb wear. Link to comment Share on other sites More sharing options...
cdarza Posted March 13, 2015 Report Share Posted March 13, 2015 This is the likely culprit to my engine roughness and drop in rpm. Link to comment Share on other sites More sharing options...
FastEddieB Posted March 13, 2015 Report Share Posted March 13, 2015 Good possibility! Link to comment Share on other sites More sharing options...
Roger Lee Posted March 13, 2015 Report Share Posted March 13, 2015 Now you need to figure out where all that came from. The fuel pump has a fine mesh screen in it so it either came from the discharge side of the pump or the hoses after it. The old fuel pumps didn't corrode if some moisture got inside, but these new ones will. This debris doesn't look like moisture caused debris. Link to comment Share on other sites More sharing options...
cdarza Posted March 13, 2015 Report Share Posted March 13, 2015 The mechanic i am working with mentioned that the corrosion looked like it came from the carb bowl itself. I will investigate further though as you have mentioned Roger- thanks Link to comment Share on other sites More sharing options...
FastEddieB Posted March 13, 2015 Report Share Posted March 13, 2015 On a BMW "Airhead" motorcycles, the float bowls are at a low point and can collect water. I've even had that water freeze, holding the floats up. In any case, that water working on the aluminum can cause the aluminum to corrode, as may be the case in your photos. On a plane, there should be a low point drain or gascolator before the carbs. Hence, for the most part water should not be able to fight gravity and migrate back up to the float bowls. Maybe in a humid environment some tiny amount of condensation can occur in the air above the floats, and then gradually accumulate? In AZ, Roger might be unlikely to see that very often. In coastal environments, especially with salt air, this could be more of an issue. In any case, maybe annually is not often enough to drop and check the float bowls. Since its pretty easy to do, let me suggest quarterly checks, just in case. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted March 13, 2015 Report Share Posted March 13, 2015 That's a lot of debris. Is it magnetic? Stick a magnet to it that will tell you a lot. Link to comment Share on other sites More sharing options...
Tom Baker Posted March 13, 2015 Report Share Posted March 13, 2015 On a BMW "Airhead" motorcycles, the float bowls are at a low point and can collect water. I've even had that water freeze, holding the floats up. In any case, that water working on the aluminum can cause the aluminum to corrode, as may be the case in your photos. On a plane, there should be a low point drain or gascolator before the carbs. Hence, for the most part water should not be able to fight gravity and migrate back up to the float bowls. Maybe in a humid environment some tiny amount of condensation can occur in the air above the floats, and then gradually accumulate? In AZ, Roger might be unlikely to see that very often. In coastal environments, especially with salt air, this could be more of an issue. In any case, maybe annually is not often enough to drop and check the float bowls. Since its pretty easy to do, let me suggest quarterly checks, just in case. Eddie, a few summers ago I was working on a carb, and had pulled the float bowls and set them on the table. The airplane had 100LL in it at the time. In a fairly short period of time the fuel level had dropped and there was quite a bit of water in the bowl. It was a really hot and humid day, but still a little surprising how quick it happened. Link to comment Share on other sites More sharing options...
FastEddieB Posted March 13, 2015 Report Share Posted March 13, 2015 Another anecdote - I had the front brake on an R100GS begin to stick a little. It was little tiny white crystals blocking the tiny fluid return hole. Living in S FL. I assumed they were salt crystals. Just basically confirming that condensation can occur in a very small enclosed space. Link to comment Share on other sites More sharing options...
FredG Posted March 13, 2015 Report Share Posted March 13, 2015 Some pilots use the isopropyl alcohol product, "iso-HEET", in their fuel systems to prevent water accumulation. Any opinions? Link to comment Share on other sites More sharing options...
Roger Lee Posted March 13, 2015 Report Share Posted March 13, 2015 The ethanol in fuel does piratically the same thing as the Heat product. They both absorb and hold water in solution and then it just burns through with the fuel instead of allowing the water to accumulate in larger pools on the bottom of tanks and the like. Heat worked better in the days before fuel with ethanol. The problem is when water in the fuel sits in a carb bowl and some of the moisture falls out and you get a few drops just sitting on the bottom of the carb. Most times this just ends up flushing through the carb. If the plane has long periods of sitting then the water has some corrosion effects on the aluminum carb bowl. I have seen a tiny amount and I have seen carb bowls from FL. completely encrusted and had to be replaced. Water in a carb bowl can look like his debris, but his is far worse then you usually see. This definetly is more than just water. Usually you see and couple of tiny specs. I have shown many an owner. I think his moisture has almost mixed with some tiny particle debris. This debris many times sticks to the bottom of the bowl and needs to be scraped out which looks like what was done to his bowl. It may or may not be the rough running problem. I would remove the idle jet while the bowl is off and manually clean the idle jet. The main jet is usually large enough to flow fairly large particles (up to a point of course). You can clean this bowl with a little scotchbrite and reuse it without any issues. Link to comment Share on other sites More sharing options...
Steven Posted April 28, 2015 Report Share Posted April 28, 2015 On two occasions over the past few weeks I experienced some engine roughness and about 10% reduced RPM during the takeoff climb. It both cases it resolved within about a minute and I continued my flights without further incident. RPM on takeoff with full throttle only reached about 4600 instead of 5000+ and the engine seemed a bit rough. But on several other takeoffs the engine ran normally. Does this sound like a fouled spark plug issue that clears itself up ? I admit to being a bit tardy with my oil change, now overdue at 50 hours since the last. I use 100LL fuel. I think I'm also due for a carburetor overhaul or replacement after 7 years and 500 hours on my 2008 CTLS. Is it safe for me to fly the plane to my mechanic ? The local mechanics won't work on a Rotax. I think it's safe to fly, but I'm not absolutely sure. Of course gremlins are always potentially lurking with or without symptoms. Darn those gremlins ! Link to comment Share on other sites More sharing options...
FastEddieB Posted April 28, 2015 Report Share Posted April 28, 2015 As usual, I would check the float bowls first. And with them off, use a bright light and an inspection mirror to look up into the jets. As far as operating with a known deficiency, I would try to invoke The Most Conservative Action rule. Link to comment Share on other sites More sharing options...
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