A tire valve is a high tension spring, will not work in a compression tester. You need a low tension Schrader valve made for compression testers or they will not read accurately. Link – https://miltonindustries.com/products/miltonr-deluxe-compression-tester-replacement-valve-core-box
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.
