Replacing Engine Fuel Pump

[Hartstoc]

Originally Posted by AlexPeterson

Is it just me, or are these engine mounted fuel pumps a real PITA to install? I have rotated the engine until the plunger is as far up as it goes. I can get the pump in all the way, as long as it is tilted a little bit. So far, so good. The problem arises when I try to get the socket head cap screw started. Because of interference between the screw head and the pump casting, I'm not able to get it properly aligned for starting the threads. The only way to get alignment of the screw is to pull back the fuel pump a little, which causes the lever to pop up above the plunger. AARRGG.

Any tricks would be appreciated. I have glued the gasket to the pump, so that "trick" is already used.

Thanks!

Mine was mounted with cap screws with allen-wrench socket- heads, and they are drilled for safety wire. I?ve permanently removed my engine driven pump so no longer need them and would be happy to mail them to you unless you have solved the problem by now. Just have to make sure I can get shorter bolts that will work to secure the cover I?m bolting onto the mount pad.- Otis

[scsmith]

This is a great thread - we need to keep it alive for those that come after us.

I still have not won this battle yet. I went out and tried the grease trick with the stickiest grease I could find. No joy. Doesn't help that it is 95F here. Maybe if it were colder.

Anyway, the waxed string/safety wire trick is brilliant. I will do that tomorrow.

It would make life much easier to shorten the screws, BUT the amount of thread engagement into the case would be potentially inadequate. It might be fine to take 3/16" off the screws, but it might not. I won't do it.

Knowing that you can see in through the left mag hole is encouraging. It means I have to re-time my Light Speed hall sensor afterward, but that is a small price to pay to be SURE the lever is properly engaged on the plunger.

[N184DA]

Having that left mag removed also allows you to route the string through the mag access, rather than slipping it between the pump and flange.

The way I did it was to basically tie the string off at one of the engine mount tubes, nice and tight, through the mag hole. Left it that way until the pump was in and the bolts were tight.

And you are correct, having the mag out is a small price to pay for knowing that the pump arm/pin are seated correctly.
And as an added bonus, makes the safety wire a little easier to install.

[scsmith]

Originally Posted by N184DA

Having that left mag removed also allows you to route the string through the mag access, rather than slipping it between the pump and flange.

The way I did it was to basically tie the string off at one of the engine mount tubes, nice and tight, through the mag hole. Left it that way until the pump was in and the bolts were tight.

And you are correct, having the mag out is a small price to pay for knowing that the pump arm/pin are seated correctly.
And as an added bonus, makes the safety wire a little easier to install.

Another time when I wish the forum had a 'like' button. Thanks.

[digidocs]

I talked to Tempest about installing the pump and they claim that you can actually reach in the L mag hole and hold the plunger up with your hand (where it contacts the camshaft). Not verified, but a good source...

[N184DA]

That is true,,
But I found I needed both hands to manipulate the pump, to orient the holes,, and to start the bolts that do not align when the pump is square on the mounting flange.

[scsmith]

Originally Posted by digidocs

I talked to Tempest about installing the pump and they claim that you can actually reach in the L mag hole and hold the plunger up with your hand (where it contacts the camshaft). Not verified, but a good source...

A great tip for those three-armed mechanics.

[WAustin]

Hi All

This was sent to members of our chapter of the Sports Aircraft Association of Australia (SAAA). I didnt go through all seven pages of replies, so maybe this has already been posted.

Link is to another forum that has hints on replacing the engine driven fuel pump.

Here it is: https://www.matronics.com/forums/vie...php?t=16775207

Hope that helps someone.

Cheers

Wayne

[BruceW]

Used the safety wire trick for keeping the plunger up. Got it on the second try. Really had to tension the wire to keep the plunger up.
Great use of this forum.
Thanks to all.

[gasman]

Better off to use regular string instead of wire. String has way more drag and will hold the plunger in place with far less pressure.