B7500 loses rpm and then recovers briefly

[Family Style]

I own a B7500
I have recently run out of fuel and changed the fuel filter.
Engine starts and runs and after about five minutes loses rpm and then recovers only to lose Rpms again. I installed both the upper an lower o rings on the fuel filter and replace clear fuel filter base recently.
Do I need to bleed air out? How?
Bad fuel pump?

 

[mendonsy]

If it is starting OK it is probably not air in the lines. That will usually cause a no start condition.
It sounds like something is restricting the fuel flow. Here's a couple of ideas:
1) Loosen the fuel cap. They sometimes get plugged and cause a vacuum in the tank.
2) Something may have been sucked into the fuel line in the tank when the fuel got low. Make sure you have good flow to the filter.
3) Some dirt may have been disturbed when the fuel ran out and plugged up your new filter.

 

[North Idaho Wolfman]

Along with Mendonsy's suggestions, are you 100% sure there is no gasoline or water in the fuel.

 

[Family Style]

If it is starting OK it is probably not air in the lines. That will usually cause a no start condition.
It sounds like something is restricting the fuel flow. Here's a couple of ideas:
1) Loosen the fuel cap. They sometimes get plugged and cause a vacuum in the tank.
2) Something may have been sucked into the fuel line in the tank when the fuel got low. Make sure you have good flow to the filter.
3) Some dirt may have been disturbed when the fuel ran out and plugged up your new filter.

I have thought about fuel restrictions. I pushed up on the check valve on the bottom of the filter and had good flow. There may be something floating in the tank that causes interment fuel flow. Is there another vent besides the one on the cap?

Fuel is fresh and does not have gasoline in it.

 

[mendonsy]

I have thought about fuel restrictions. I pushed up on the check valve on the bottom of the filter and had good flow. There may be something floating in the tank that causes interment fuel flow. Is there another vent besides the one on the cap?

Fuel is fresh and does not have gasoline in it.

The only vent to the fuel tank is the cap. Try running it with the cap loose first. If that solves the problem you can take the cap apart and clean it. The air inlets are around the outside edge of the cap. Take a look at this thread:
http://www.orangetractortalks.com/forums/showthread.php?t=12195

 

[Family Style]

Replacing the cap did help.
Fuel gage is still not working and stalls have become more intermittent.
Pumped all the fuel last night and pressurized the tank. I drilled a hole in a flat plate and placed it over the tank. I blew air into the tank through the hole. I can't really see the tank. It does not look like it will collapse?
Is this possible?
How does the fuel sending unit work? Could there be parts suspended in the tank?
Is there a schematic of the tank assembly on line?