intake flow problem

when I'm using the standard cut off valve on my intake side, it seems the flow is not enough, going through to the pump.There are bubbles... then no bubbles in a cyclic, rhythmic action and when I have the pool cleaner hose hooked up to vacuum, it temporarily stops altogether. However, when I take off the valve (leave it on the pool but disconnect the tubing and put it into the pool over the top, it runs perfectly, even when the vacuum line is on. Seems to me the valve doesn't permit enough water to flow though. I was thinking of cutting the 1 1/2 in. hole larger to 2 1/2in and just connect the tubing without the plunger cut off valve. Intex makes one size valve but has 2 different inside-the-pool filter screens small and large and I've tried both. Has anyone heard of this problem? I am using a Intex model 633T krystal clear filter pump and an intex modelcs8110 salt system. thanks, jim,

Just to clarify, this is a valve between the skimmer and the pump? If that is the case you need that valve so you can open and clean out your pump basket. Are there bubbles coming out of the return? If not it sounds like your pump is cavitating due to flow restriction. Your valve might be busted or clogged, replace it, don't chuck it. However I am no expert and not familiar with intex pools, someone else might have better advice.