markmn Posted February 9, 2011 Report Share Posted February 9, 2011 Title says it all. My P2008 less than a month old on its third fuel pump. My A&P did not want to believe it was the engine driven fuel pump again. He checked all the venting, andair fuel selector, all the fuel lines and the pressure guage. We flew and I showed him the engine would starve for fuel about a minute into climb out unless the electric pump was on. Gauge also showed no pressure. Finally put another pump on and it worked. The second pump worked fine for a few hours also so he is still not 100% convinced. I said I would ask here for any other ideas or possibilities. Any thaughts? Mark Link to comment Share on other sites More sharing options...
Roger Lee Posted February 9, 2011 Report Share Posted February 9, 2011 Hi Mark, Those pumps have been known to be bad right out of the box, but 3 pumps in a quick succession might be close to a record. The newer pumps come with a thicker gasket than the older ones, too. The pump stem tip needs a little lube and not put in dry. It is the copper anti seize. You should not be running the auxiliary pump at the same time as the mechanical one unless you have a problem. You might give Jeremy a call at CPS and see if he has seen this many bad pumps on one plane. I know Jeremy and myself have seen 2, but not 3. Link to comment Share on other sites More sharing options...
Tom Baker Posted February 9, 2011 Report Share Posted February 9, 2011 The way I read it is 2 bad pumps, and the third is working for now. Link to comment Share on other sites More sharing options...
Roger Lee Posted February 9, 2011 Report Share Posted February 9, 2011 Your right Tom. I misread his post. In that case I have seen this and I know CPS and others have seen a bad pump right out of the box. Link to comment Share on other sites More sharing options...
markmn Posted February 9, 2011 Author Report Share Posted February 9, 2011 Thanks for the replies. I appreciate it. Yes two failed pumps and on the third. Wondering about not running the electric pump unless needed. The checklist provided by tecnam north america say to use the electric pump on takeoff and landing. In your opinion should is this correct? Mark Link to comment Share on other sites More sharing options...
Tom Baker Posted February 9, 2011 Report Share Posted February 9, 2011 Thanks for the replies. I appreciate it. Yes two failed pumps and on the third. Wondering about not running the electric pump unless needed. The checklist provided by tecnam north america say to use the electric pump on takeoff and landing. In your opinion should is this correct? Mark A couple other airplanes that I'm familure with run the electric along with the mechanical pumps for take off, but these are not Rotax powered airplanes. The thinking is if the engine driven pump fails the electric is already online. Tom Link to comment Share on other sites More sharing options...
Roger Lee Posted February 9, 2011 Report Share Posted February 9, 2011 Hi Mark, Full time electric pumps have caused issues in the past. It is one of the reasons a few years back Rotax had many replace their mechanical pumps which was supposed to help take care of that particular over pressure issue. The vast majority of 912 owners do not run electric pumps along side the mechanical one and you don't see them falling out of the air from bad pumps. My last plane had that electric pump option in it. I only turned it on just before start up so it would prime the system and I could hear if it was operational. Then I shut it off and started the engine. I never ran it at the same time with the mechanical one. That plane had 900 hours on it when I sold it without ever a cough on the fuel delivery. The answer here of course is that you need to make the final decision. Not one CT has an electric back up pump. So long as you have a high wing and the pump fails it will fail open. You may not be able to fly full throttle, but you should have enough gravity fed fuel to fly at a reduced power setting so long as the fuel lines go straight down to the engine. Link to comment Share on other sites More sharing options...
markmn Posted February 10, 2011 Author Report Share Posted February 10, 2011 The third pump went out today after half an hour in the air. Something is amiss somewhere. Could it possibly be the cold weather here? Temp was 10f on the ground G3X said 4f up in the air. Several of the flight school planes were out flying. The windshield also cracked today. The plane was out of the heated hanger about 15 minutes and I was taxiing ( how do you spell taxiing ) to the runway and heard something. Could not figure out what it was. Later as i was flying around I noticed a 4 in crack on the copilot side starting at the top. Must have been cause by the expansion/contraction of the cold weather or? I flew in colder weather than this bringing it back from virginia and no problems. Have any of you replaced a windshield and what do I need to know about it? Wonder how long it will take to get a windshield from italy. I guess I will find out how good tecnam parts support is. Mark Link to comment Share on other sites More sharing options...
Roger Lee Posted February 10, 2011 Report Share Posted February 10, 2011 Hi Mark, Were you running the electric pump at the same time? You may need to pull the gear box to check the lobe that the fuel pump plunger rides on? The newer gaskets are thicker than the old ones so I hope you have used the new gaskets that came with the pump. A thinner gasket on a new pump might cause a pump failure. The crack has to be either from the cold, not my first pick, but more likely from stress and flexing of that area. Sounds like you need to call the Remos distributor and ask. Depending on age and time you would have a warranty claim. The window will have to be cut out and then ground out of the recessed mounting area. The new one gets glued in and needs to be clamped. Then a filler like Bondo to seal up around the edges and then new paint. Sometimes the parts flow out of Europe for all our planes can take months. I hope you have some states and the distributor is jolly on the spot for you. Link to comment Share on other sites More sharing options...
markmn Posted February 10, 2011 Author Report Share Posted February 10, 2011 Roger, I was not using the aux pump. I was purposly not using it even on takeoff to see if that was possibly the problem. Guess not. I will ask my mechanic if he used the new gasket or not. I wanted to take a trip tomorrow. I know my plane will run partial power without a fuel pump. Is it reasonable to go and use the electric Pump? As far as the windshield was thinking about drilling a hole in the windshield at the end of the crack to prevent further cracking and appying clear tape over the crack and drilled hole? It this a good idea or? how big a hole should I drill if I do? Anything else I can do so the plane does not get grounded till I can get a new windshield? Mark Link to comment Share on other sites More sharing options...
Roger Lee Posted February 10, 2011 Report Share Posted February 10, 2011 Hi Mark, Yes you should stop drill the crack. 1/8" drill should be sufficient and tape won't hurt, but it won't stop it from cracking further, the drilling should. Drill it on both ends. The plane could fly on the auxiliary pump, but you need to get that fixed ASAP and I don't know if you really want to go fly though. I'm out of ideas so you may want to give Jeremy at CPS a call or Aaron at Lockwood and see if they have seen any thing like this or other things to check. Link to comment Share on other sites More sharing options...
FastEddieB Posted February 10, 2011 Report Share Posted February 10, 2011 A couple other airplanes that I'm familure with run the electric along with the mechanical pumps for take off, but these are not Rotax powered airplanes. The thinking is if the engine driven pump fails the electric is already online. Tom A few data points... 1) My Sky Arrow has a ROTAX and high wings but calls for the boost pump on for takeoff and landing. BUT, in my plane the fuel is in a fuselage tank and the engine is higher, so failure of a single pump would lead to fuel starvation - so it makes sense. 2) In my plane, with the boost pump on, the fuel pressure shows barely in the green. When I turn it off, fuel pressure drops (on the gauge) to very close to zero before climbing back up to the green in about 10 seconds. Never a hiccup, but strange. 3) With about 220 hours, I'm on my original pump, Link to comment Share on other sites More sharing options...
Runtoeat Posted February 10, 2011 Report Share Posted February 10, 2011 With a 3rd pump failure, it's time to tear down the fuel pump drive system and find out what's causing failure. I wouldn't fly with just a backup fuel pump, My personal thoughts. As for getting a new windshield, start the process going for this now by calling the Tecnam U.S. distributor. Part delivery for LSA's, including our CT's, can take months. Roger's suggestions for calling CPS or Lockwood is good advice. Leading Edge Airfoils in Wisconsin is also a very knowledgeable company when it comes to Rotax maintenence and repair. Brett is a good guy to talk to there. Link to comment Share on other sites More sharing options...
coppercity Posted February 10, 2011 Report Share Posted February 10, 2011 I would not fly the plane. I know you want to make your trip but flying with a known critical problem is not a good idea. Remember the accident chain, a fuel issue is the first link in the chain, next is the decision to fly, the third could be the failure of the backup pump. I know it sucks to be down, but it's far better to be safe. Link to comment Share on other sites More sharing options...
GlennM Posted February 11, 2011 Report Share Posted February 11, 2011 I am not sure about airworthiness, but I have seen cracks in aircraft windows stiched up with safety wire. Picture football stitches between holes on either side of the crack. It is a little more effort than just sticking clear tape over the crack. The stop drilling is probably best unless the stress was not relieved when the crack opened. On the fuel pump side, how do you know the fuel pump itself has failed? What about the gascolator filter (if it has a gascolator)? Fuel can be forced through a partially blocked filter with higher pressure typical of the electric fuel pump setting. What about a crimped fuel line upstream of the fuel pump and downstream of the electric fuel pump? I don't know the fuel system design, but I would assume the electric fuel pump is somewhere on the firewall while the engine driven one is on the engine. If the affected area were upstream of the electric pump, both pumps would be affected. I am not sure a visual inspection would be able to detect a problem unless you were looking at it with the engine at full throttle and the electric fuel pump was off. Was the fire sleeve removed for the inspection? The fuel line could be collapsing during operation and not seen under the firesleeve. Also, the fuel tank outlet may have something partially blocking it. Link to comment Share on other sites More sharing options...
markmn Posted February 11, 2011 Author Report Share Posted February 11, 2011 I decided it best to stay home today. Thanks all for the advice. Tomorrow my mech and I are going to bypass the gascolator and electric fuel pump and see If that changes anything. Just so you know when we start the engine it shows good fuel pressure. Then when you add power the pressure gradually drops. Dont worry we are doing this on the ground. We have checked all the fuel lines, venting, return lines, gascolator while tha plane was in the hangar. Let several gallons gravity thru and pump thru with electric pump and no restrictions.If we do not find anything by bypassing the elec pump and gascolator we are going to pull fuel from an alternate source and see what that does. None of the failed pumps have leaked. We dissasembled A failed pump today and could not se anything wrong. It is interesting that fuel pumps are on backorder from rotax. There are none available. Tim at tecnam NA is sending a pump off a plane that has been working for us to try also. Any other suggestions? Mark Link to comment Share on other sites More sharing options...
markmn Posted February 19, 2011 Author Report Share Posted February 19, 2011 We are not sure but it looks like the fuel pump issue is temperature related. I have not posted lately because I wanted to fly the plane a few times before reporting back. One day when the temp was 30F we were trying to simulate the problem again on the ground under power and the fuel pressure started to drop as usual and the it came back again. This was surprising as we had not seen this before. My mech Bruce at wells aviation was already wondering if it was temp related because when he dissambled a previously failed pump he did not find anything wrong but thought the diaphram was plenty stiff. We ended up insulating the fuel pump and closing the cowl nacelles? sp? Have not had a problem since. Bruce believes the springs in the pump were flexing the pump not pumping after the pump got cold enough. We were flying in temps between 10 and 20F. Likely colder up at alt. It is hard to believe I was the only one flying in these temps. Coincidently Tecnam said all rotax fuel pumps were on backordered at the time. Mark Link to comment Share on other sites More sharing options...
Roger Lee Posted February 19, 2011 Report Share Posted February 19, 2011 Hi Mark, The temp issue is hard to believe because many CT's and other Rotax 912's fly in even colder temps. Link to comment Share on other sites More sharing options...
coppercity Posted February 19, 2011 Report Share Posted February 19, 2011 That does seem a little odd, I have flown my CT for hours up at altitudes of 13500' to 14500' where the temps were -10 to -20C without any indication of fuel pressure problems. Link to comment Share on other sites More sharing options...
markmn Posted February 19, 2011 Author Report Share Posted February 19, 2011 On the p2008 the prop wash goes derectly onto the fuel pump thru the nacelle. We believe very little engine heat radiating to the fuel pump under power. How is the cowl setup on the CT? Mark Link to comment Share on other sites More sharing options...
coppercity Posted February 19, 2011 Report Share Posted February 19, 2011 The CT is pretty tightly cowled so it stays warm I'm sure. Link to comment Share on other sites More sharing options...
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