Reply to thread

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Message: <blockquote data-quote="MrGiggles" data-source="post: 518961" data-attributes="member: 22613">The type of tester can make a difference, if you are using an adapter with a long hose that has the schrader valve in the middle, it is not going to give you a precise reading, the volume of that hose is effectively added to the combustion chamber, decreasing the compression ratio. It makes less of a difference on engines of bigger displacement, which is what most compression testers are designed for. Your 70hp triple is likely ~250cc per cylinder, where an automotive four stroke is double or triple that. In summary I wouldn't put much faith in a single test. Try your gauge in another outboard that runs well and see what it reads, or try a shorter adapter if you have one that works.</blockquote>