Proper way of checking compression

[genetoo]

As most of us know Compression is number one in importance when buying and starting to work on a unfamiliar outboard. My Question : In my case a 2 cyl Maybe a dumb question ?? Your screwing in your compression gauge in one of the 2 cyls one at a time to check compression, do you leave the other spark plug in while turning it over so you can spin it faster & easier;or doesn,t it make any difference ? gene In Mn

[seakaye12]

You should remove all the spark plugs to make spinning the motor over easier. You should also ground each of the spark plug leads. Never rope a motor over with the spark plug leads un-connected unless you can positively shut off the ignition in some manner.

[Anonymous]

Thanks, great tip!

[joecb]

And another thing, unlike with a 4 cycle engine there is no need to hold the carburetor throttle open when doing a compression test…. Think about it !

Joe B

[2fast4me]

“Think about it”— Both ports are open at the bottom of the stroke. Jim

2Fast4Me

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