N456TS Posted September 4, 2015 Report Share Posted September 4, 2015 For those who are interested, attached are photos of the components of the Rotax fuel pump. Ignore the drilled hole. That was made to quickly punch out the valve and screen assembly. And ignore the mess. It's a machine shop. Link to comment Share on other sites More sharing options...
Runtoeat Posted September 5, 2015 Report Share Posted September 5, 2015 Excellent pictures. Thanks. Can this pump be rebuilt? Link to comment Share on other sites More sharing options...
Roger Lee Posted September 5, 2015 Report Share Posted September 5, 2015 Hi Dick, No Link to comment Share on other sites More sharing options...
N456TS Posted September 5, 2015 Author Report Share Posted September 5, 2015 You would have to come up with your own parts to rebuild it. Considering that a whole pump only costs $100, there is no need to reinvent the wheel. However, if they were in the $500 range, I'm sure someone would make an aftermarket kit or repair service. Link to comment Share on other sites More sharing options...
FredG Posted September 5, 2015 Report Share Posted September 5, 2015 Thanks for the photos. If I am not mistaken, this looks like a conventional diaphragm pump with a one-way flow/check valve. That seem correct to you? Link to comment Share on other sites More sharing options...
N456TS Posted September 6, 2015 Author Report Share Posted September 6, 2015 That's correct. And a screen. I took it apart to confirm there was nothing found in the screen. It was replaced due to a leaking shaft oil seal. Link to comment Share on other sites More sharing options...
Anticept Posted September 6, 2015 Report Share Posted September 6, 2015 The internal screen is a big reason why you want to make sure you have good filtration before fuel gets to the fuel pump. These cannot be opened and cleaned out (stupid, but that's the rule). Link to comment Share on other sites More sharing options...
Roger Lee Posted September 6, 2015 Report Share Posted September 6, 2015 Easy enough to check for debri in the fuel pump no matter which one you have. Take it off and flow fuel backward through the filter. It is an open circuit and anything in there will flush out. Link to comment Share on other sites More sharing options...
Anticept Posted September 6, 2015 Report Share Posted September 6, 2015 ??? I swear it has check valves... otherwise how would a diaphragm pump work? Or do they just never completely close? Link to comment Share on other sites More sharing options...
Roger Lee Posted September 6, 2015 Report Share Posted September 6, 2015 The check valve works on an abrupt pressure change from one direction. A smooth even flow through will not trigger the valve. It is one way so it can build pressure and doesn't work in reverse. It opens in reverse. This is why when they fail they fail open. Link to comment Share on other sites More sharing options...
Anticept Posted September 6, 2015 Report Share Posted September 6, 2015 That works . And I know how a checkvalve works, I just find it interesting that the design won't close the check valve until there's a significant and abrupt delta p. Link to comment Share on other sites More sharing options...
Runtoeat Posted September 6, 2015 Report Share Posted September 6, 2015 N456TS (if you can provide a first name it would be nice). How did you know it had a bad oil seal? Are there visual indications of this? Maybe oil coming out a vent hole in the pump? Link to comment Share on other sites More sharing options...
N456TS Posted September 7, 2015 Author Report Share Posted September 7, 2015 N456TS (if you can provide a first name it would be nice). How did you know it had a bad oil seal? Are there visual indications of this? Maybe oil coming out a vent hole in the pump? Bradley. Yep, oil seeping out the seal and making its way down the vent hose. Link to comment Share on other sites More sharing options...
Roger Lee Posted September 7, 2015 Report Share Posted September 7, 2015 On the old AC and Pierburg pumps this was not normal for fluid to leak out the weep holes. This can however be normal at times to have a small seep from this new Corona pump into the vent tube. It shouldn't be a flow, but a small amount of fluid does happen. I hope you didn't toss this pump out too soon. Link to comment Share on other sites More sharing options...
N456TS Posted September 7, 2015 Author Report Share Posted September 7, 2015 No, it needed to be replaced. A Rotax shouldn't be leaking. Are you pre-lubing the seal prior to installing? Link to comment Share on other sites More sharing options...
Roger Lee Posted September 7, 2015 Report Share Posted September 7, 2015 You should put a little copper anti seize on the plunger tip for first start, but other than than no lube anywhere else. The new Corona pumps can seep some fluid. I got this right from Rotax. It shouldn't be constant or a flow, but you can have a seep now and then. Link to comment Share on other sites More sharing options...
Anticept Posted September 7, 2015 Report Share Posted September 7, 2015 Copper antisieze? Do you mean white lithium grease? Assuming you mean on the end of the pump that contacts the eccentric cam in the gearbox housing... Link to comment Share on other sites More sharing options...
Roger Lee Posted September 7, 2015 Report Share Posted September 7, 2015 "Assuming you mean on the end of the pump that contacts the eccentric cam in the gearbox housing." On the tip of the plunger that contacts the eccentric. I mean copper anti seize. Copper anti seize is also what is used to assemble the gearbox. On the first oil change of the engine's life and after a gearbox rebuild (if done right) you can at times see some tiny little speckles of the copper in the oil with a flashlight. If you did an oil analysis on these two oil changes you would have some copper show up in the analysis. White Lithium may work, but I don't think it is as durable and holds up on the pressure as well for those first few seconds. Link to comment Share on other sites More sharing options...
Doug G. Posted September 8, 2015 Report Share Posted September 8, 2015 Why doesn't Rotax mention that in the Service Bulletin? They say grease or even engine oil. Link to comment Share on other sites More sharing options...
Roger Lee Posted September 8, 2015 Report Share Posted September 8, 2015 If you use any grease you would need to make sure it is compatible with the oil system. That would be like white lithium grease. Some are not. Oil would work, but has no body and tends to run off before the owner ever gets around for a startup. Copper anti seize has good staying power and anti metal wear for that short startup run so the oil can take over. They did recommend for a short while Kluber grease for use in the gearbox, but then found out is wasn't very compatible with the oils. They are now back to copper anti seize for gearbox maint. needs. Link to comment Share on other sites More sharing options...
Anticept Posted September 8, 2015 Report Share Posted September 8, 2015 That must be something that just changed, last year it was lithium or kluber grease Link to comment Share on other sites More sharing options...
Roger Lee Posted September 8, 2015 Report Share Posted September 8, 2015 Kluber. When Rotax came out with that I rushed to buy a EXPENSIVE tube of this for gearbox jobs. You had to buy it from Kluber and it only came in one caulking gun size. During my next Rotax class update they said don't use it. Anyone need a tube of grease??????????????? I guess I'll use it for bearings or zerks? Link to comment Share on other sites More sharing options...
FastEddieB Posted September 8, 2015 Report Share Posted September 8, 2015 This seems a bit anal. I assume the pump will spend its entire life lubricated with engine oil. Should suffice for the few moments on initial startup. Right? Link to comment Share on other sites More sharing options...
Roger Lee Posted September 8, 2015 Report Share Posted September 8, 2015 Most likely. It's just what I was taught and do. Bottom line you absolutely don't want a dry start and score the eccentric. Link to comment Share on other sites More sharing options...
N456TS Posted September 9, 2015 Author Report Share Posted September 9, 2015 Have you been reporting your leaking pumps to Rotax? They shouldn't be leaking new, or close to new. I'm not talking about lubing the shaft end. I'm talking about pre-lubing the oil circuit for the engine oil seal within the pump. If you don't, it will remain dry for a fair bit of time. The seal will not get the required lube for correct operation. As a result, the seal will fail prematurely. Link to comment Share on other sites More sharing options...
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