Ovation boost pump failure

[egp]

Does anyone have an idea on why my boost pump seemingly may have failed on my M20R Ovation 3? I planned on flying today however after turning on the master I turned on the low boost and it sounded totally different than usual. I then decided to try the high boost and there was no sound at all. I'm totally puzzled as I flew yesterday and all was normal.

[rbridges]

do a search for boost pump, and you'll see several threads.  I know the pump that came with the older planes is a POS based upon what I've read.  I don't know if they changed them in the newer birds.  

 

Yours may need a rebuild, but I'd have my IA look at it to make sure it's nothing else.

[egp]

I checked previous treads but mostly saw questions on operation and none on failure. I'll do another search.

[rbridges]

I know the older mooneys had duke pumps. There is an option to replace it with a Weldon pump. I don't know what yours has. There are threads that discuss costs to rebuild the pumps.

[egp]

I'm just curious as to how both pumps seemingly failed. I only use the low boost pump to start. Both pumps have had almost zero use,.... And why have both pumps failed,....do both switches (high & low) run one pump? Seemingly so! Both pumps checked out fine yesterday,....today just the lights came on indicating the pumps were functioning but no pump sound,....just baffling!

[Hank]

First thing to check is wiring--are the connections tight? Good ground? Is the switch itself good? When turned on and making different sounds, are you showing fuel pressure? Start with the easy stuff before pulling the fuel pump.

[egp]

Weird electrical hum on low with no pressure and engine won't start. No sound on high. Pushed her back in hanger and canceled trip.

[egp]

Thanks,....weird electrical sound on low and no sound on high. As I said previously the indicators light on both but engine doesn't start. Pump or pumps defiantly not working.

[Cruiser]

from the maintenance manual.

 

"The electric fuel pump is in the bottom left forward section of the fuselage, aft the firewall. "

 

"The single auxiliary electric boost fuel pump is controlled by two switches. The LOW boost switch is utilized for engine starting procedures and to purge fuel vapors from the system during high temperature conditions, either heat soak conditions or high OAT.

The HIGH boost (guarded switch) is utilized for use if the engine driven fuel pump malfunctions and will provide sufficient fuel for partial power operation of the engine."

 

Do you see fuel flow when you turn the boost pump switch on? Also a voltage controller for the boost pump is used to set fuel pressure.

 

There is either an electrical problem not supplying power to the pump or the pump is bad. 

[egp]

Any idea where the boost pump is located in a late model ovation? I'm pretty handy and I'm curious enough to check it out tomorrow to see if maybe its something as obvious as a loose wire or the like......

[egp]

Thanks cruiser,....I will do a visual on the pump tomorrow. My guess is the pump is bad but maybe ill luck out and find a loose wire. I'll let you know....thanks again.

[N601RX]

I think I remember a post from a while back and the problem turned out to be a large resistor. You might try to find the old thread.

[egp]

Thanks everyone for your thoughts & input. I'll post what the problem & fix turns out to be. Hopefully we get up & running this week....

[BobAustin]

Just replaced the Weldon pump on my 1985 201/Missile (original pump).  Lasted 29 years so not a POS.  The 201 only has high boost.  Overhaul about 800.

[rbridges]

Just replaced the Weldon pump on my 1985 201/Missile (original pump).  Lasted 29 years so not a POS.  The 201 only has high boost.  Overhaul about 800.

 

I think that's the option for the older ones.  They come standard with a Dukes pump.  I've heard a lot of grumbling about it.

[egp]

Well the problem ended up being a failed (original equipment) Dukes pump. The most troubling part of all of this is the pump started working again after we attached an external power source and continued to work when reattached to the aircraft battery power. We believe it found some sort of dead spot or something. Intermittent problems are the most frustrating issues to me! I was really tempted to just leave the original pump in service but knowing it had failed once I made the decision to bite the bullet and change it out. It surly would of failed again and next time I may not be as lucky and would probable get stuck away from home or worse! So after a lot of research we decided to replace the Dukes pump (part #5791-00-1) with a new Weldon pump (part #A8152- supplied by Aircraft Accessories in Tulsa Oklahoma. Cost new with no core is $828.50. If I had a Weldon core I could of purchased a rebuilt for $780.00. (Not much savings anyway) so hopefully we will be up and running in the next day or two. Thanks again for all the input.