Not an original idea by any means, but I thought it might be worthwhile to mention this.
This time of year, I bring wood into the mudroom by the wheelbarrow load, which requires that I prop the storm door open while I wheel the wood in. At one point, the closer would not stay open, and I replaced it . Cost around $10 or $12 bucks for a new closer. And then a few years later, intermittently I had the same problem...some days it was fine, like carrying in the groceries, but wheel in some wood, and it would start to close on the wheelbarrow
. So I started to use a wedge to hold the door open, which worked.
Then we had our new woodstove delivered quite a few years ago now, and one of the guys went to set the door to stay open, and of course that little metal piece did not do its job and slide back down the rod. He just reached in and grabbed a penny from his pocket, opened the door wide and slid the metal piece back out, putting the penny between the piece and the pneumatic closer. Problem solved.
So if your closer closes just fine, but won't stay open, save yourself $9.99 on a $10 closer, and keep a penny near the door. Here is a picture.