Boost pump acting funny

[TravelVeteran]

Curious if there is a way to overhaul these or if I need to find new.  this is for a 1965 M20C Mark 21, 180 HP.  

During use it kinda makes the fuel pressure needle bounce around instead of a consistent increase in pressure. It sounds kinda funny too. 

[PT20J]

https://aeromotors.azurewebsites.net/

[DXB]

Just went through same, it died shortly thereafter.  Details on replacement options posted here:  

 

[TravelVeteran]

Update, i turned it on and the operation is back to normal, however i see that it leaks fuel through the drain hole during use. i thitnk the part number on this thing is

610153 or  4140-00-19




 

[Shadrach]

47 minutes ago, TravelVeteran said:

Update, i turned it on and the operation is back to normal, however i see that it leaks fuel through the drain hole during use. i thitnk the part number on this thing is

610153 or  4140-00-19




 

See @PT20J's post above.  Call Aeromotors and schedule and exchange/overhaul. I suspect that pump doesn't owe you anything in terms of typical Dukes service life.  The good news is the the overhauled unit will be improved in terms of performance and durability.

[PT20J]

If it leaks through the drain, it means that the seals are leaking internally and it needs to be overhauled 

[DXB]

Pro tip based on recent experience to spare you my pain once you get the replacement installed: The fuel in the lines around the pump will drain out during the swap, possibly creating an air lock that will prevent it from generating fuel pressure at the transducer. Don't run the pump dry for more than a few seconds.  Instead pump the throttle (carb accelerator pump) with the pump on and mixture in to pull fuel into the carb bowl.  Once you see fuel pressure starting to rise, cut the mixture before it floods, and let fuel pressure come up to top of gauge before turning the pump off.  Check everything below for leaks at this point before closing it up and firing up. 

[Shadrach]

2 minutes ago, DXB said:

Pro tip based on recent experience to spare you my pain once you get the replacement installed: The fuel in the lines around the pump will drain out during the swap, possibly creating an air lock that will prevent it from generating fuel pressure at the transducer. Don't run the pump dry for more than a few seconds.  Instead pump the throttle (carb accelerator pump) with the pump on and mixture in to pull fuel into the carb bowl.  Once you see fuel pressure starting to rise, cut the mixture before it floods, and let fuel pressure come up to top of gauge before turning the pump off.  Check everything below for leaks at this point before closing it up and firing up. 

Did you get your pump from Aeromotors? One of the improvements they make is to eliminate the “wet side” fuel lubricated sleeve bearing and replace it with a dry side sealed bearing. This means the Aeromotors pump is not subject to damage from dry running. Ole Bartlett the owner of Aeromotors told me that his pumps have been test run dry in excess of 10hrs with no signs of damage.

[DXB]

58 minutes ago, Shadrach said:

Did you get your pump from Aeromotors? One of the improvements they make is to eliminate the “wet side” fuel lubricated sleeve bearing and replace it with a dry side sealed bearing. This means the Aeromotors pump is not subject to damage from dry running. Ole Bartlett the owner of Aeromotors told me that his pumps have been test run dry in excess of 10hrs with no signs of damage.

The only improved new one I was aware of as a drop in replacement is from CJ Aviation.  That one still has a sticker on it that says do not run dry.  Sounds like the Aeromotors ones are better still. 

[Shadrach]

29 minutes ago, DXB said:

The only improved new one I was aware of as a drop in replacement is from CJ Aviation.  That one still has a sticker on it that says do not run dry.  Sounds like the Aeromotors ones are better still. 

That’s my understanding.  I priced both when I needed overhaul. Talking to Ole sold me. I posted details of that conversation and my initial impressions in 2019. They’ve done a good job of holding prices. $450 in 2019 and $500 in 2023

[TravelVeteran]

16 hours ago, DXB said:

Pro tip based on recent experience to spare you my pain once you get the replacement installed: The fuel in the lines around the pump will drain out during the swap, possibly creating an air lock that will prevent it from generating fuel pressure at the transducer. Don't run the pump dry for more than a few seconds.  Instead pump the throttle (carb accelerator pump) with the pump on and mixture in to pull fuel into the carb bowl.  Once you see fuel pressure starting to rise, cut the mixture before it floods, and let fuel pressure come up to top of gauge before turning the pump off.  Check everything below for leaks at this point before closing it up and firing up. 

great tip thank u