Search the Community

Hi Guys, I’m looking for a M20J boost pump Pn:A8163-B Fuel Pump-Weldon. Seems very difficult to get one. Any hint or suggestions? Tks

Mooney save back at home ! M20J MSE 243164 (1990) The issue (description by local mechanic on site, at that time I'm 240nm away at home): Battery Master and Alternator ON: The fuel pump and the starter do not work, the lights are working. Battery is full charged, no issue. To make the boost pump and starter work, have to put the avionics switch ON, then everything works. The engine can be started. But, if avionics ON the boost pump can not switch OFF (beside pulling the CB). It’ just running, even the boost pump switch is off. Technically I could fly the plane home for further inspection and repair. I’m now afraid about a possible short circuit somewhere. Any Idea? __________________ Update 6/6/22 pls see below too _________________________ Thank you very much for all the support and good advice. The error description above came from the French mechanic in Colmar LFGA. I had tried, on the way to Colmar, sitting 10h in a train, to trigger Mooneyspace as additional support, typed on the iPhone. To me, the description seemed so strange, I had tried to have you as such a good source on my side. On site, I then had remote support from my avionics professional who did the avionics conversion (2xG5, GNS 530/430 WAAS+210, AT1, ADL) two years ago, as well as from another avionics examiner, both from Germany. On site, the situation turned out to be different than described by the French mechanic. The boost pump did not work. Navigation switch on or off did not matter. I did measured through the boost pump switch, which is also a CB - Mooney standard wiring. It works normally. A separate Boost Pump CB does not exist therefore also. the French mechanic has probably confused that with the fuel flow CB. Probably just the boost pump is defective or has/had a short circuit. We are now clarifying this at home. I was able to start the Mooney without the boost pump, normal procedure, but with the avionics switch off. So, at least for me, there is no longer any connection of the issue with the avionics bus, as far as can be seen at least now. I had wondered about an error that had already occurred 2 months ago. Therefore, I had a possible dependency with the avionik relay not seen as entirely impossible. The Alt Field CB jumped out once, but could be pushed in again. No further issue. This occurred again on the flight to Colmar. Not on the return flight. I can't see any connection with the boost pump. Maybe it's just "lause and fleas" at the same time. We are now looking into this at home. Again thank you all. Any advice on both problems is of course highly appreciated by me.

Aircraft is a Mooney M20F, engine is a Lycoming IO-360-AIA. It's equipped with a Weldon 8163A electric boost pump (certified replacement for the original Dukes). POH start procedure specifies mixture to idle cut off, boost pump on to pressurize the lines, then advance mixture to prime. When the boost pump is turned on with the mixture at idle cutoff, pressure builds to about 25 PSI and is rock solid. The pump makes a fairly loud hum while it's on, of course, and the frequency of the humming noise (i.e. the speed of the pump) decreases a bit as the fuel line pressurizes. We don't prime for hot starts, but sometimes we prime when the airplane is "sorta" hot, e.g. sat on the ramp for an hour or two during a $100 hamburger run. Sometimes there is still vapor in the lines in these cases. If so, the pump seems to "strain" a little as pressure builds, and the frequency of the humming noise from the pump warbles a little. I've always considered this normal, during the 10+ years this particular pump has been in service. Now, after a recent annual, my airplane partner said he heard the hum from the pump warble a bit even on a cold start. This morning I turned on the pump for a cold start and let it run a full 30 seconds or so before priming. Sure enough, the speed of the pump varied a little after the lines were pressurized. Fuel pressure needle never wiggled, it was rock solid at about 25 PSI as expected. We're now trying to decide if the warbling frequency from the pump is "normal" or not. I confess I've never paid much attention to steady vs. warbling sounds from it, since I know some variation is normal as the lines pressurize (especially if vapor is present). The pump has about 10 years of service on it, and probably somewhere in the neighborhood of 2000 on/off cycles, so I suppose it's possible the brushes on the motor are going. It's also possible the system is sucking air from somewhere. There are no blue stains around the pump or gascolator upstream from it, that would indicate an obvious leak. But the bowl of the gascolator was R&R'd at the recent annual, to inspect and clean the screens. It was reassembled with new gaskets and safety wired, but that doesn't guarantee a good seal of course. What says the collective wisdom of the board? Leave it alone? Inspect the system? Replace the pump now even though it's not obviously defective? We're not necessarily trying to avoid the cost of a new pump. But we are reluctant to replace what may be a perfectly good pump, due to the risk of a maintenence-induced problem in the swap. Any/all opinions appreciated.