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  #11  
Old 02-13-2007, 03:57 PM
gstone gstone is offline
 
Join Date: Aug 2006
Location: Johnson City TN
Posts: 196
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Hi, I'm a sure rookie but had to pass this idea. I've used a piece of rubber tubing to start aggrevating bolts and spark plugs before. Just cut a short piece of flexible tubing that fits over the bolt head??? and then you have flexibility to maybe get it started then drive with tools. ?????
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Greg
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  #12  
Old 02-13-2007, 09:25 PM
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AlexPeterson AlexPeterson is offline
 
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Location: Maple Grove, MN
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Default Victory

Ok, Pete Howell and I beat this thing into submission. So, the short bolts to start and then replacing with the long bolts idea doesn't work. If the pump is tight against the housing, it is not possible to put the full length bolt in, because the housing doesn't allow for the proper angle for starting the bolt. The trick seems to have been to keep the pump about 1/4" away from the accessory case, while starting the bolts. Some sort of shims might make this easier. Pull the pump back too far, and the lever slips off the plunger. A balancing act.

It is probably a good thing that whoever designed the dang thing has probably croaked. I've worked on a lot of cars, etc., and I'm not sure I've seen a dumber setup.

Thanks for the tips.
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  #13  
Old 02-13-2007, 10:37 PM
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petehowell petehowell is offline
 
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Default Some minor swearing was required....

Alex is right, the design is just stupid from a maintenance standpoint.

It was a good evening in the hangar with Alex and my kids. Hard to beat that.
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  #14  
Old 03-08-2009, 05:04 PM
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n5lp n5lp is offline
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Join Date: Apr 2006
Location: Carlsbad, NM
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Default Fuel pump blood brother

Quote:
Originally Posted by AlexPeterson View Post
...If the pump is tight against the housing, it is not possible to put the full length bolt in, because the housing doesn't allow for the proper angle for starting the bolt. The trick seems to have been to keep the pump about 1/4" away from the accessory case, while starting the bolts. Some sort of shims might make this easier. Pull the pump back too far, and the lever slips off the plunger. A balancing act.

It is probably a good thing that whoever designed the dang thing has probably croaked. I've worked on a lot of cars, etc., and I'm not sure I've seen a dumber setup...

Yep, what Alex said. This thing is just unbelievable.

First the decision to use hex bolts. That means you have to come in straight but you can't do that because the housing is in the way. Those bolts also make it much harder to safety wire, because the wire goes astray whilst it is in the cavity. Oh, and if the safety wire holes line up sideways you have about 1/8"clearance to the case which also greatly adds to the safety wiring challenge.

As has been said, it is critical to have the pushrod engaged with the arm when you install the pump but you can't just put the pump in position because then you can't start the bolts. The canny designer made the position where the bolts can be started almost exactly the position where the rod jumps off the arm. Probably none of this is a huge deal if you can get to the back of the engine, but it is hard when you can just get part of one arm in and don't have clearance to even operate safety wire pliers or dykes.

Anyway, I actually got the thing installed today and made two failed stabs at the safety wiring. I'll come back at that tomorrow with hemastats. The tips from this forum were a big help; in particular the round end allen wrench was a huge help.

The reason I changed the pump out is not because it failed; it is because it was working too well.

Quote:
Originally Posted by videobobk View Post
...I had five A&Ps tell me a fuel pump couldn't fail to a too-high situation, but mine did. It overflowed the carb. The fuel pressure will never go higher than what it takes to force fuel past the float valve, something around 9psi, at least on my carb...
I have been using the pump for 10 years but for the last 6 months the fuel pressure has been too high, like Bob's. For me this has only intermittently caused a problem, and only while taxiing for takeoff. The fuel pressure would go up to around 8 or 9 flooding the carb and causing very rough running. I would keep it running by fiddling with the mixture, near idle cutoff, and after the runup the pressure would be to an acceptable, but still high value, and there would be no problem until the next cold start.

Also like Bob, I asked many mechanics about this (myself, I'm not one of them mechanical guys) and none of them felt like it could really happen. If anything, an older pump should put out a lower pressure, they would say. What could I do though? All I could think of was a new pump. After I finally got it on today, I ran the airplane and it ran great. The fuel pressure was 5 PSI, which I just haven't been seeing. Even when it was within limits, it was usually around 7 or 8 on the initial start of the day.

So I don't have enough experience to say for sure the new pump solved my problem, but it looks good so far.
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Last edited by n5lp : 03-08-2009 at 06:59 PM.
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  #15  
Old 03-08-2009, 07:39 PM
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AlexPeterson AlexPeterson is offline
 
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Larry, when I saw the picture I thought maybe you had gotten into a fight with a cat. Thanks for the laugh - and for commiserating with me (and confirming that it wasn't just me not knowing what to do!).

I think next time I'll figure out a way to hoist the plane in a way that I can turn it upside down. Seems like less trouble.
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  #16  
Old 03-13-2009, 07:54 PM
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revenson revenson is offline
 
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Location: Tucson, AZ
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I'm facing this right now, and concur that the pump housing design is AWFUL.

I've heard that one can add some grease to the pin inside the engine, helping to stick it in the up position. I haven't tried it, and I'm not going to.

I want to be VERY confident that during installation the pin in the engine has not slipped down, with the associated possibility of a mismatch with the pump plunger.

Since I haven't yet mounted the engine, I will tip up my engine (as if it were on an engine stand). This won't eliminate the wrestling with the bolts, but at least I can be sure the pin has not slipped down while installing the pump.

Roger, Tucson, 7A finishing.
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  #17  
Old 03-13-2009, 08:55 PM
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N941WR N941WR is offline
 
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Quote:
Originally Posted by n5lp View Post
...Anyway, I actually got the thing installed today and made two failed stabs at the safety wiring. I'll come back at that tomorrow with hemastats. The tips from this forum were a big help; in particular the round end allen wrench was a huge help...
FYI - The other day when I was looking at the Lycoming OH manual I found a drawing of the fuel pump installation. Guess what, the drawing only showed the safety wire going through the side of the hex head and out the middle, not through both sides as mine is currently wired.

If you wire yours this way, just make sure you pick up the left side so it can't loosen.
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  #18  
Old 03-13-2009, 08:59 PM
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n5lp n5lp is offline
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Location: Carlsbad, NM
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Quote:
Originally Posted by N941WR View Post
FYI - The other day when I was looking at the Lycoming OH manual I found a drawing of the fuel pump installation. Guess what, the drawing only showed the safety wire going through the side of the hex head and out the middle, not through both sides as mine is currently wired...
Bill, I appreciate the tip. I am planning to go at mine again this weekend and that may help.
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  #19  
Old 03-13-2009, 10:42 PM
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erich weaver erich weaver is offline
 
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Location: santa barbara, CA
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I've taken the fuel pump off twice now (dont ask) and fully agree that installing this bugger really sucks - it really wasnt any easier or quicker the second time. The one thing I have learned however - stop worrying about holding the plunger in the up position while you cajole the pump into place and struggle with the socket head screws. Focus on getting one screw started (the outside one is easier - duh) while holding the pump flange just off the engine. When that first screw is just started, it will help you keep the pump positioned, while still allowing enough movement for you to manipulate the lever and get the second screw started. If you can push the pump flange flush up against the engine in its correct postion by hand, the lever IS in the correct position (under the plunger), and you have it made. If it wont go up against the engine by hand, its not, and you need to back off and manipulate it around until you can get it into position. What you absolutely must avoid is forcing the pump into position by cranking down on the screws with your allen wrench - bad juju there. If the screws arent going in easily and smoothly and/or the pump flange isnt mating up flush against the engine case, you do not have it positioned correctly.

A small mirror properly postioned (I taped it in place) to let you see the inside screw is very helpful. One last warning - be sure to use a sealer on the screw threads, as the holes for them penetrate through into the interior of the engine case, and you risk an oil leak (the reason for my forced second removal/reinstallation).

erich

Last edited by erich weaver : 03-14-2009 at 09:04 PM.
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  #20  
Old 03-14-2009, 07:46 AM
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uk_figs uk_figs is offline
 
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Default interesting thread

As I do not recall this being as big a challenge as stated in this thread I wonder what the symptoms are of an incorrect installation. If I remember correctly my installation was similar to the previous post i.e get it lined up and push against casing to install bolts. The pump has been delivering around 4.5 psi for the past 65 hours of operation.
What happens if the pump is not installed correctly?
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