nosky2high

M20F IO360A1A fuel pump failure

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Taxied out this past weekend and the engine quit during run up. After a quick experiment, the engine would only idle with the electric boost pump on. A new replacement lycoming fuel pump and gasket was ordered from spruce and is arriving today. 

Requesting advice and any helpful procedures to replace the fuel pump on my 67 M20F. Are there any other proactive maintenance tasks or recommended improvements while I’ve got things apart?

Thanks in advance.

Anthony

 

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I did this on my C 2-3 years ago. You'll need (or at least I did) a 2nd pair of hands and a bucket of patience.

I didn't take much off other than the battery box, but you don't have yours up there.  It's not a big part really.

Maybe replace the fuel hoses while you're at it. Moving to the newer prop governor would give you more room to work if you want to spend some money, but again not wholly necessary.

The hardest part is being blind putting the tongue on the correct spot in the engine without having much maneuvering room to make all the geometry work.

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Thanks for posting the video.  If you don't understand how a fuel pump works, you will after watching.  If you don't understand why either fuel or oil is coming out your old and failing fuel pump's drain, it is explained at the 10 minute mark.  Good stuff.

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I did my fuel pump when I had the mags out for 500 hour inspection.  My oil cooler is rear mounted and I was doing baffle work so I don’t know if that would be in the way or not.  

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They said you have to remove a mag.  I did not.   I did sacrifice a 5/16 allen wrench about 2" long then used a socket and ratchet.   Turning the prop and getting the right place is key.  Make sure the plunger is in the right place.  Safety wiring is "fun".     Google search mooneyspace for cooling shield.   You may or may not have one.   There should be a cooling hose pointed at the pump.

It's like doing one on a chevy V8.   Only takes more time.

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A thread to a thread....  Some have some don't.   I would think a pain in the arse to get the pump and the shroud on.

 

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When you are done, make sure the fuel line B nuts are tight and torque seal them. Had one back off years ago creating a leak. 

Skip

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There is a follow-up thread for high fuel pressure that effected some engines that got new fuel pumps...

If you have that challenge, there is a thread or two around here for that...

Best regards,

-a-

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When I replaced mine, we had to loosen the top left motor mount in order to get enough clearance from the firewall for the plunger to go back in correctly.   

Triple check you have the correct pump.  Some people got the wrong one that delivers too much pressure.  

Edited by Browncbr1

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If the fuel lines are older I'd replace those as well.

This is the only mechanical pump I've heard off. I believe both sides provide pressure so I've seen them replaced because they are weak on the pressure gauge but totally failing is scary.

I did notice when I got me new engine from Lycoming that it now runs right at the top of the green where before it was near the middle.

-Robert

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On September 10, 2019 at 10:24 AM, RobertGary1 said:

If the fuel lines are older I'd replace those as well.

This is the only mechanical pump I've heard off. I believe both sides provide pressure so I've seen them replaced because they are weak on the pressure gauge but totally failing is scary.

I did notice when I got me new engine from Lycoming that it now runs right at the top of the green where before it was near the middle.

-Robert

It wasn't a total failure, the engine would run at high rpms, but not smoothly.

There was some trace amounts of fuel leaking from the old pump. I've gone ahead and inspected the entire fuel injection system since the flow divider and servo yellow tags are dated 2005.

we fly way too much night/IMC cross countries to have any doubts in our engine and components.

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12 hours ago, Aviationinfo said:

Sorry for thread creep, but I have to wonder how often these things fail between overhauls?  

Exceedingly rarely 

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