Glass Bowl Fuel Pump?

[Mudviper]

I just purchased and installed a new glass bowl single pump style fuel pump on my CJ3A. Not to familiar with these pumps and tried to do a search on them, but couldn't find much on them. My question, although might be a dumb one, is how does the top glass bowl feature supposed to work? What I mean is there are two halves of the bowl, one toward the front of the engine and one towards the back. The half that is toward the front fills about half way and stays that way pretty much, but the other side doesn't fill very much. Is this the way they are supposed to work? Want to make sure that I have it set up correctly. Does the screw nob on top of the glass do anything or is that just to hold the glass bowl in place? 

Thanks
Steve

[athawk11]

Here is a photo of the typical guts on a single action mechanical fuel pump.  This one has a steel cover where yours is glass, but the function is the same.  On the right, you see the diaphragm. This is moved by the cam shaft making contact with the lever on the back of the pump.  This diaphragm movement drawls the fuel from the gas tank.

On the left you see the inside of the top of the fuel pump. The two brass circles are valves.  One valve lets the fuel into the top.  The other valve will let this same fuel be delivered to the carburetor.  In your case, the glass top fuel pump allows you to see this fuel move from the tank to the carburetor.

The glass will not generally fill all the way up.
 
The screw on the top is holding the glass against a gasket between the housing and the glass.  You might see occasional bubbles.  If so, you should tighten this screw.  You don�t want bubbles.

Hope this helps.

Hawk

[athawk11]

Here is your typical glass top.  The inlet side (closest to us) also has a screen (brass).  This filters out large particulates that may get in to the fuel tank.  You can remove the glass and clean this filter screen if needed.

 

[Mudviper]

Thanks athawk11. The one I took off was a metal top and actually put out a little bit more pressure then the glass top on. The metal top was putting out 3 psi while the new glass top is putting out just over 2 psi. Just wasn't sure if the right side half of the glass bowl was supposed to be more then a 1/4" of fuel in it.

[athawk11]

2 PSI is pretty low for a single action fuel pump.  I would expect to see maybe 4 PSI. 

There is a spacer between the engine block and the original dual action fuel pumps used on a 3A.  You may know this, but this spacer should not be used when switching to a glass top single action fuel pump. 

Hawk

[Mudviper]

2 PSI is pretty low for a single action fuel pump.� I would expect to see maybe 4 PSI.�

There is a spacer between the engine block and the original dual action fuel pumps used on a 3A.� You may know this, but this spacer should not be used when switching to a glass top single action fuel pump.�

Hawk

There is no spacer between the block and pump

[Mudviper]

Just for *crap and giggles I went to the local auto parts store and pick up another cheap pressure gauge and that one is reading a little over 3 psi, so the other gauge isn't that accurate. Not sure how accurate the new one is either..lol

[athawk11]

I helped my Father in Law install a new submersible irrigation pump last weekend. Right out of the box, the pressure gauge read 15 PSI.  Very frustrating.

[Mudviper]

Over the weekend I changed out the fuel lines and switched from running 5/16 to 3/8 line, read somewhere on here that 3/8 fuel line was better. When I did that, the glass bowl does not fill up now, but I am also running some pretty big fuel filters, on before and one after the pump. With the bigger fuel line and filters, is it normal not to see any fuel in the bowl?

[scoutpilot]

Given a good diaphragm and properly functioning valves, as long as the brass screen is covered with fuel, the pump is performing its job. The air in the bowl is to maintain a certain level of pressure in the pump. If there is NO fuel in the bowl there is a blockage or an air infiltration leak in the supply line from the tank.

[Mudviper]

Given a good diaphragm and properly functioning valves, as long as the brass screen is covered with fuel, the pump is performing its job. The air in the bowl is to maintain a certain level of pressure in the pump. If there is NO fuel in the bowl there is a blockage or an air infiltration leak in the supply line from the tank.

There is about a 1/4" of fuel in the bowl now. When I first started it up and let it run for awhile, the bowl would be nearly empty. Went out there the other day and started it up and the bowl filled to about 1/4", so all is good..lol

[Mudviper]

What do you do about keeping water out of the fuel pump through the vent hole. I would like to take the Willys out trail riding and I see the vent hole on the pump in pretty low. Is there much chance of getting water in the pump while it is running if I go through a water hole?

[scoutpilot]

I�ve heard of no one complaining about water in the pump. Lots of deep off-roaders out there. And remember, the Jeep was not designed for your Grandma to drive to church on Sunday. Here�s a video of the military prepping for a beach landing. Notice no mention of the fuel pump.
http://www.vidinfo.org/video/3067038/water-proofing-willys-jeep

[Mudviper]

I�ve heard of no one complaining about water in the pump. Lots of deep off-roaders out there. And remember, the Jeep was not designed for your Grandma to drive to church on Sunday. Here�s a video of the military prepping for a beach landing. Notice no mention of the fuel pump.
http://www.vidinfo.org/video/3067038/water-proofing-willys-jeep

That's a pretty wild video. From what I was reading though, the fuel pumps used in the military versions did not have a vent hole. It probably will not be an issue, so I will not worry to much about it

[scoutpilot]

If it bothers you, tape a piece of mastic over the vent Just before entry and remove it immediately after exit from the water. It should not be a problem for you as the pressurized block will prevent much of anything getting in. That vent is to relieve block pressure within the pump.