Primer button is cracked

How old is the machine? Do you leave gas in it in long periods of time? Do you use e10 fuel? I would simply just replace the bulb. You can get them cheap on Amazon or in a big box store for a little more. Usually a few screws you need to take off ( you may need to take off other stuff as a well depending on your model. Realize these bulbs are just thin tube like material. Try to use ethanol free premix. Big box stores or select few stations ( if any) in your area will have some. Ethanol is small engines worst nightmare. Wrecks havok on everything. Start with replacing bulb, simple YouTube search and 5 minutes you'll be done. Use ethanol free fuel /premix. The primer bulb should not have thay much pressure. If you've done any maintance make sure you put the lines on correctly