I have an above ground pool , just started up for the season. I have excessive back pressure coming thru skimmer after I shut off filter. A couple of things are happening. One is my suction hose broke last year, the only extra hose I had was a 1 1/4 size. The old one was a 1 1/2 hose. (i have one ordered and coming in )  but in the mean time have to run the pool. Will that smaller diameter hose from skimmer to pump cause air to come into the system? Or should I look elsewhere. There are air bubbles coming from return after running for awhile.  Another thing is a drip coming from the pump drain hole when pump shut off. I bought a new plug with “O” ring and replaced but still drips. I tried loosening it , tightening it, teflon tape, lubrication, everything.

Almost ready to apply some sealant to plug and call it a day, sense I never use it.  Could that be my problem or should I just try to change that skimmer to pump hose back to 1 1/2 ??  Also, before anybody ask, it is an above ground, with the system set up below the water line. 

Thanks for any help