Johnson Outboard Compression Chart Johnson 175 1998

Re: OUtboard Cylinder Compression? Dan, From the mid-late 80's or thereabouts outboards were lowered in compression to around 120psi in order to cope with the newly introduced Unleaded fuel at typically 89-91 RON (Research Octane Numbers) as opposed to the previously used Super (approx 95 RON).

1973-1991 Johnson Evinrude Outboard 60 HP-235 HP Workshop Manual 2-STROKE. If the piston and rings can't compress the air-fuel mixture in the cylinder so the spark can ignite it, the engine won't run well, if at all. As the piston travels up and down in the cylinder, the piston rings seal against the cylinder wall so the air/fuel mixture can be compressed at the top of the cylinder on the upstroke. (Illustration: ©2016 Mirto Art Studio)An outboard gas engine needs air, fuel, spark, compression, and unobstructed exhaust - in the right amounts and at the right time. A lot can be learned by checking the engine's ability to compress the gas/air mixture. Here's why and how it's done.There are four distinct phases in a four-stroke cycle: induction, compression, power, and exhaust. Thank you for reading.Ĭhecking Compression On An Outboard EngineStory And Photos By John TigerA compression check can tell a lot about the health of your outboard engine. Parts ordered from this website may or may not be in dealer stock at the time of order. Mastertech may make improvements to this site at any time. Changes are periodically added to the information herein. The information, software, products, and services published on this web site may include inaccuracies or typographical errors. This information is disseminated in good faith, however MasterTech assumes NO LIABILITY whatsoever in regard to this service. Model Number Code InformationPlease review our before you place an order.DISCLAIMERThe information provided on these pages is correct to the best of my knowledge, however the MasterTech makes no warranty, express or implied, regarding the use of, results of, or liability created from, application of this data.

Johnson Outboard Compression Chart Johnson 175 1998.

Johnson outboard compression chart