I agree. We had one on our pop up pool years ago and it sounds like there is a small leak in the suction side hose somewhere OR the hose between the pump and the filter. Thats what happened on ours, that hose got just a pin hole sized hole in it which we thought was no big deal but it produced lower suction as it was pulling air - eventually it blew right open at that spot! Maybe think about replacing that hose - its a short hose and cheap enough to do. Or, its the other hose? Anywho, those hoses are plenty inexpensive. Thas actually not a bad pump for that pool (you can run a smaller suction side pool cleaner on it no problem)

We use silicone lubricant on all our pool parts - its stored with the supplies all the time so we never get tempted to try something else.