Boost Pump Replacement

[Fritz1]

Found boost pump leaking a little last weekend, no new Weldon pumps in stock anywhere, ordered overhauled pump form Aircraft Accessories of Oklahoma Monday morning, wanted to fly airplane Monday afternoon though, boost pump dead, no start. Removed boost pump, applied 24 V directly to terminals, stone dead, did not budge. New pump arrived on Wednesday, label from overhauler says overhaul every 10 years, mine was 24 years old with about 1900h. I was lucky it failed on the ground at home and not in the air or on the ground far way from home. My A&P IA says he has replaced many of them on Lycoming engines and they tend to run about 2000h. I put a note in my logs to replace it after 1000h. What does everybody think, what is typical service life of boost pump?

[Shadrach]

19 hours ago, Fritz1 said:

Found boost pump leaking a little last weekend, no new Weldon pumps in stock anywhere, ordered overhauled pump form Aircraft Accessories of Oklahoma Monday morning, wanted to fly airplane Monday afternoon though, boost pump dead, no start. Removed boost pump, applied 24 V directly to terminals, stone dead, did not budge. New pump arrived on Wednesday, label from overhauler says overhaul every 10 years, mine was 24 years old with about 1900h. I was lucky it failed on the ground at home and not in the air or on the ground far way from home. My A&P IA says he has replaced many of them on Lycoming engines and they tend to run about 2000h. I put a note in my logs to replace it after 1000h. What does everybody think, what is typical service life of boost pump?

 

Actual runtime? I’ve had Dukes pumps that I don’t think lasted 20 hours of actual operation. The Aeromotors updated dukes are as good or better than the Weldons which are supposed to be pretty good. Not sure what your SOP is but your Weldon likely started leaking because of age not use. Reads like you got a lemon.

With all of the positive Pireps on MS about Aeromotors, is there a reason why you elected not to use them?

[Fritz1]

good point, had no idea there was an Aeromotors pump to replace the Weldon, wanted bird back in the air asap

[Fritz1]

New boost pump runs great off panel switch, still does not run off throttle switch, the parts catalog lists a voltage regulator for the boost pump which does not make sense since the  Bravo has a single speed 24V boost pump, soo dumb question is there any relay or regulator on the throttle switch circuit, if not throttle switch either needs adjustment or got fried when boost pump failed, boost pump breaker never popped, 

[LANCECASPER]

31 minutes ago, Fritz1 said:

New boost pump runs great off panel switch, still does not run off throttle switch, the parts catalog lists a voltage regulator for the boost pump which does not make sense since the  Bravo has a single speed 24V boost pump, soo dumb question is there any relay or regulator on the throttle switch circuit, if not throttle switch either needs adjustment or got fried when boost pump failed, boost pump breaker never popped, 

Probably just out of adjustment

[PilotX]

16 hours ago, Fritz1 said:

New boost pump runs great off panel switch, still does not run off throttle switch, the parts catalog lists a voltage regulator for the boost pump which does not make sense since the  Bravo has a single speed 24V boost pump, soo dumb question is there any relay or regulator on the throttle switch circuit, if not throttle switch either needs adjustment or got fried when boost pump failed, boost pump breaker never popped, 

I note @LANCECASPER point about adjustment. Interesting when I was last at sea level'ish airport, my boost pump came on but it doesn't at my home drone ~5600'.

[LANCECASPER]

26 minutes ago, PilotX said:

I note @LANCECASPER point about adjustment. Interesting when I was last at sea level'ish airport, my boost pump came on but it doesn't at my home drone ~5600'.

It's just a microswitch, it shouldn't have anything to do with altitude. I believe it should come on any time you're at full throttle.

[IvanP]

Had similar issue on my Bravo. Sometimes the boost pump would turn on when thhe throttle was advaced to foll open, sometimes it would not. After examining the miscroswitch in the engine compartment, i found that the rather flimsy lever actuating the microswitch was slightly misaligned. 5 min fix, no parts were needed. 

[Fritz1]

Yep, will check out microswitch next, need an oil change anyhow

[PilotX]

I know it is a micro switch, mine is probably misaligned but that last time I was at sea level, my boost pump and came on a full throttle. Just an anecdote. Stranger things have happened.

[Jetpilot86]

The microswitch has been a pain in mine. Somehow it got removed so the throttle would never activate the pump. Got it reinstalled and adjusted but it doesn’t cut off until about 33.5” now. I’ve since gone to climbing at WOT, so I guess I need to wonder how much wear and tear it puts on the pump itself. 

[Fritz1]

checked out the microswitch and it is dead, still need to order replacement and install, think it just got fried by stuck boost pump instead of the boost pump breaker being popped, thereafter the stuck boost pump tripped the breaker in the panel switch, 2000h on the airframe, just about enough for the boost pump microswitch and the boost pump to fail jointly, I was lucky that this happened in front of my hangar

[IvanP]

On 8/19/2024 at 10:24 PM, Jetpilot86 said:

The microswitch has been a pain in mine. Somehow it got removed so the throttle would never activate the pump. Got it reinstalled and adjusted but it doesn’t cut off until about 33.5” now. I’ve since gone to climbing at WOT, so I guess I need to wonder how much wear and tear it puts on the pump itself. 

This can probably be easily fixed by adjusting position of the bead on the throttle cable that hits the switch actuating lever. Mine only actuates at full throttle and even minor movement from full will stop the pump.  

[Jetpilot86]

On 8/22/2024 at 3:15 PM, IvanP said:

This can probably be easily fixed by adjusting position of the bead on the throttle cable that hits the switch actuating lever. Mine only actuates at full throttle and even minor movement from full will stop the pump.  

I’m told by Maxwell that there is a flat spot on mine that hangs it up a little. It’s on the agenda for next annual.