dtoelke Posted March 11, 2015 Report Posted March 11, 2015 I use the low boost pump before hot starts to force out evaporated fuel in the lines. Yesterday I had a mechanic standing outside and he noticed when the low boost pump was turned on fuel started coming out of a drain located a couple inches fore of the gascolator drain. He told me he thought it was the boost pump drain and indicated the pump was going bad. Can anybody confirm this statement? Repair is $1000 plus labor so I want to make sure this is the issue. Thanks in advance! Quote
carusoam Posted March 11, 2015 Report Posted March 11, 2015 From my O experience... This is typical of seals going bad... The leak is diverted out a drain to the outside. It is often difficult to notice because you prime the system while in the cockpit and don't see it unless somebody outside tell you... Overall it is a good system to have in working order. It isn't just to get the engine started... Best regards, -a- Quote
dtoelke Posted March 11, 2015 Author Report Posted March 11, 2015 Thanks! Do you know if the seals can be overhauled or if an entirely new pump is necessary? Quote
dtoelke Posted March 11, 2015 Author Report Posted March 11, 2015 Nvm spoke with the service center down in LA and they recommended an overhauled unit + core. Quote
Mike A Posted March 11, 2015 Report Posted March 11, 2015 I just went through this 3 weeks ago. My 231 was in the shop already and when they went to do the run-up, fuel started flowing out of the drain. I replaced mine with an overhauled unit - $700 from Ru Lon Aviation (Google searched). Shop charged me 1.5 hrs for removal and install. Quote
chrisk Posted March 11, 2015 Report Posted March 11, 2015 I just went through this too. I replaced the Dukes pump with a new Weldon 18020-A. The pump is a drop in replacement and was $793 from Spruce. If you want to go the rebuilt route, you might want to look at www.aeromotorsllc.com I believe they charge $400 +shipping to rebuild a Dukes 4140-00-19A pump. Quote
kortopates Posted March 11, 2015 Report Posted March 11, 2015 I use the low boost pump before hot starts to force out evaporated fuel in the lines. Yesterday I had a mechanic standing outside and he noticed when the low boost pump was turned on fuel started coming out of a drain located a couple inches fore of the gascolator drain. He told me he thought it was the boost pump drain and indicated the pump was going bad. Can anybody confirm this statement? Repair is $1000 plus labor so I want to make sure this is the issue. Thanks in advance! Good info on your options for repair. I'll only comment on the hot start. I recommend, per the TCM maintenance & operation manual to use the High Boost pump with mixture at Idle cut off to recycle the hot fuel in the line with cool fuel from the tanks. In a Lyc you are only purging air by pressuring the the fuel line, but in a Continental you are also able to recycle the fuel. At Idle Cut Off, it prevents any fuel from going into cylinders and just sends the hot fuel back to the tank at the fuel valve. Using high boost will recirculate it twice as fast than using the low boost. Of course its the same pump just running on less volts in low boost mode. I use 15-20 sec on high boost. Quote
dtoelke Posted March 12, 2015 Author Report Posted March 12, 2015 That's great advice. Does it matter what position the throttle is in? Also, in what other circumstances would you normally use the boost pumps? I thought they were typically only used in emergency situations (main pump out, after switching tanks following accidental exhaustion, etc.). Quote
carusoam Posted March 12, 2015 Report Posted March 12, 2015 Yes... Check your plumbing. For some Continental fuel systems, fuel is returned to the tank or selector valve. (Great for hot starts) If your POH says use full throttle and mixture in while priming, their is a reason for it... Done improperly, fuel goes back to the tank instead of priming the engine correctly... Then they say how to set the throttle and mixture prior to start... (Easy to remember?) Boost pump is used automatically in some engines at full throttle (climb settings) to provide excess fuel for cooling. Picture fuel exhausting overboard while the pump is on during climb-out. Followed by not getting enough fuel for proper cooling... I am only a PP, not a mechanic... Best regards, -a- Quote
kortopates Posted March 12, 2015 Report Posted March 12, 2015 That's great advice. Does it matter what position the throttle is in? Also, in what other circumstances would you normally use the boost pumps? I thought they were typically only used in emergency situations (main pump out, after switching tanks following accidental exhaustion, etc.). Throttle position really has no effect if just purging the lines. That's right about boost pump usage. Per the emergency procedures, which frankly are not well written in the 231, but improve in the later K model years, you use the High Boost for an engine driven fuel pump failure and you use the low boost pump for when air gets in the line causing roughness or engine surging when hot or following like your example of accidental exhaustion. The K model POH's don't call for using the low boost pump when changing tanks, but ironically they do with the bigger bore Continental models (as do the Lycoming installations) so even though its not in the book there would be nothing wrong in using it for switching tanks. Quote
dtoelke Posted March 15, 2015 Author Report Posted March 15, 2015 So I went to grab the part number from the bad pump so I could order another and found that the number is located on the top side (unviewable without taking it out). Could somebody identify this pump? It's a '79 M20K. http://mooneyspace.com/gallery/image/36485-img-0303/ Thanks so much. Edit: I should add that I would assume based on comparisons with online pictures it's either the Dukes 4140-00-19A or 1499-00-19, not sure which one (based on my research. Plane's S/N is 25-0142). What about replacing with a Weldon? Quote
dtoelke Posted March 15, 2015 Author Report Posted March 15, 2015 Update: Based on logbook entries it appears to be the 4140-00-19A. What are the pros/cons of sticking with the Dukes setup or swapping out for a Weldon 18020-A? Quote
carusoam Posted March 16, 2015 Report Posted March 16, 2015 Since the low boost and the high boost are the same pump... Is it likely to be the switch or a wire in between or something electrical vs. the whole pump? Last time I went flying, my low boost was having difficulty as well. High boost was acting normal. Maybe looking for the same gremlin... -a- Quote
carusoam Posted June 13, 2015 Report Posted June 13, 2015 ...carried to new thread... Low boost pump slowly not functioning.... Quote
DrBill Posted June 13, 2015 Report Posted June 13, 2015 I put the Weldon in mine at last annual. I now have a Dukes that I intend to send for a rebuild to Aeromotors for a spare. They claim their rebuild is for continuous duty (like the Weldon but not the Dukes). Unless someone else wants it for 0.1AMU. BILL Quote
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