\u00a9 2023 wikiHow, Inc. All rights reserved. Diagnosing a blown head gasket - can I use a compression gauge? Sounds from a cylinder adjacent to the one you are testing: indicates a bad head gasket or warped head. Once a problem cylinder is detected via a compression test or by other means, a cylinder leakage test is used to pinpoint the problem area. crysta1c1ear (Automotive) 31 Oct 06 19:15. There may not be any specs for small engines available; but I have found through experience,that a small 4 stroke (2-8HP) with a compression reading of as low as 45psi will run but will not have any power. (765) 362-1967davestriblingrestorations.com. Have your helper, fully depress the accelerator, while he is cranking the engine. 1. So I've been having some engine trouble with my 98 Mazda 626 GF 2L, specifically a low, rough idle and lack of power on acceleration. 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