Not problem with filer, it's the air coming into suction side of pump

This is a air leak on your suction side between the skimmer and the pump. You will not see water in the yard on the suction side usually, only the return. It is usually just the fittings around your pump or the seal around the pump lid, check those first and make sure you do not have a loose clamp or a damaged or dry seal. If that is not it then call in your local service guy to determine where the leak is. They will most likely pressurize your suction line to find the leak. Hope that helps.
Time to Open the Swimming Pool

Try the shaft seal?

Otherwise, you have a suction air leak somewhere on the suction side of the pump. That means somewhere between the front of the pump all the way back to the pool.
The easiest to check, least expensive and the most common, will be broken thread sealant on any 'threaded' fitting, bad O-rings or seals in valves and unions, or you have a crack in your plumbing. And... It may be underground. Good Luck

You should have 3 tubes, a fuel delivery tube, a fuel return tube and a fuel suction tube, the fuel delivery tube ( the one with the fuel filer on in the tank ) goes to the connection on the carb nearest to the pump cover held with a single screw, the other connection on the carb goes to the suction side of the primer bulb ( the shorter of the two connections ) the return to tank tube fits to the longer connection on the primer, this tube is just pushed into the top of the fuel tank,

check the suction side fitting, reset the threads and check or replace the lid o-ring. If there is not air showing in the check valve, it's more likely to be a suction side fitting leak. also be sure to check the impeller for debris.

turn the pump off, remove the lid and pump basket. reach your finger inside to see if there is any debris caught in the impeller. MAKE SURE the pump cannot come on at any point while you're working on it.
That should do the trick, if not, investigate an air leak on the suction side of the pump. Causes: bad lid 0-ring, threads on suction fitting leaking air in, or if there is a union on the suction side, make sure it's tight and the o-ring is in good condition (add lube as necessary).

I think you meant that the pump keeps filling with air. You may have an air leak on the suction side of the pump. If you turn the pump off, you should not see any water leaking out of anywhere, if you see any water drip near the suction side of the pump, you should consider that an air leak and repair it.

The problem you're having seems to be an air leak. when you connect the manual vacuum or if the system is running normally, there is not nearly as much suction that is created as when the zodiac is plugged in. The air is forcefully pulled into the system when increased suction is created.

Try replacing the lid o-ring and investigate any possible places on the suction side of the pump that could be a potential leak.

Hope this helps.

There are many causes for air getting into the suction side of the pump. The easiest thing to check is the seal around the strainer basket. Make sure there is no dirt, grass, hair or other debris across any o-rings. After cleaning the o-ring, lube it with pool & spa lube. If air persists, check the connecting fittings on the suction side. Do you hear any wheezing when the pump is turned off? If so, there is a leak in the suction piping. If you are able to locate the fitting which causes the wheezing sound, you can bandaid the leak by putting a good amount of Silicone II clear sealant on the area (and allow to dry). If you are unable to locate a leak, then an air pressure test can be performed to see if the suction side is leaking. You may also have a problem with something stuck in the suction piping. This condition causes the pump to cavitate, which is like the pump spinning its wheels. When you starve the suction for flow, it will appear like air trapped in the strainer. You can try to blow air through the line to clear it, or a snake may do the job. This problem is very difficult to resolve.

There is an air lock, so it seems. Leave filter off, on top of filter is a valve to let air escape. Keep this open until you get a stady stream of water from oulet, then close. Start pump. Not being a smart ****, besure that the water flow is correct. Skimmer to inlet side, return to pool.

I would have a check valve installed in the inlet line - Dont know if you have the manual, but pumps should be within so many feet of the water source, dependin on the suction capabilities. You probably have air in the inlet side, and if you don't have a check valve your pump may be too far away to pick up the water. You can always fill the suction side, and if you know for certain that you have water coming in, and the inlet isnt plugged up, you probably have a pump or driveshaft problem. hope this helps you, rick

1, Does the blower (discharge) side blow bunches of air??
Yes: Something is clogged from the bag to the hose end. Try blowing out the hose from the discharge side.
Or: The bag is not properly seated. Make sure that the plastic piece is properly inserted into the bag, and properly aligned and locked in place with the suction intake.
No: Something is wrong in the motor/fan assembly.
2: The hose has a plastic cover on the end farthest from the unit. Make sure that this cover is closed. If it is open, your suction will go way down.