Johnson Outboard Compression Chart

How to do them and what the results mean for you.

Johnson outboard compression chart. However i ve seen a lot of misinformation on this topic. P art is no longer. 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.

Here is everything that you need to know about outboard compression tests. I am going to make some comments about compression related to johnson and evinrude motors because am more familiar with motors from the 1950 s to mid 1980 s motors. For instance a fully functional mercury 25 hp cylinder compression value may be significantly different than that of a johnson 25 hp.

Johnson outboard compression chart chromatic tuner imt 500 manual if you are looking to replace your lower unit on your vintage johnson evinrude outboard then ebay is a great place to find a good deal. The most common being to just pull out the plugs and do a pressure test on a cold engine with out any prep work. Model year chart for johnson and evinrude outboards 1980 1999.

How to correctly compression test an outboard engine. Good results for four strokes should be 180 210 psi and two strokes should be around 110 130 psi. Johnson 8 hp outboard manuals return to top year model 1927 p 35 1930 32 k 50 1931 ok 55 johnson 8 1 hp outboard manuals return to top year model 1935 ok 75 johnson 9 2 hp outboard manuals return to top year model 1933 k 65 1934 k 70 johnson 9 3 hp outboard manuals return to top year model.

They not only vary from the reporting individual but from manufacturer to manufacturer. Results vary depending on whether the outboard is a four stroke or a two stroke. Click picture if your mfgr.

What outboard compression test results mean. Performing a compression test on an outboard engine is fairly simple. A fun old porcelain sign and ancient tools.

I own several johnson evinrude outboard service manuals and none of them given compression reference ranges. An outboard gas engine needs air fuel spark compression and unobstructed exhaust in the right amounts and at the right time.