1998 Evinrude 120 compression test

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da-murph

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Aug 5, 2003
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Can someone explain to me a safe way of doing a cold compression test on this engine? Thank you in advance.
 
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DJ

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Re: 1998 Evinrude 120 compression test

da-murph,<br /><br />1. Unplug the safety kill switch lanyard. This will disable the ignition.<br /><br />2. Move the throttle to wide open throttle.<br /><br />3. Put the tester in # 1 cylinder.<br /><br />4. Turn the engine over, with the starter, while watching the compression guage. Spin the starter until the guage stabilizes, that is your peak compression for that cylinder. <br /><br />5. Record the reading.<br /><br />6. Repeat for the other three cylinders.
 
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da-murph

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Aug 5, 2003
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Re: 1998 Evinrude 120 compression test

Thanks for the info, I have to confess that I don't have a manual yet, therefore I don't have much to work with. I don't really know what cylider is what? Are we talking from looking at the engine from the stern? If so what is the arangement? thanks for your help. joe m.
 
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airman

Petty Officer 1st Class
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Aug 9, 2003
Messages
332
Re: 1998 Evinrude 120 compression test

Don't worry about the cylinder #'s yet. All you're looking for is even compression on all cylinders and probably something over 90psi. Just make sure that you get all the spark plug wires back in the same place.
 
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Dhadley

Supreme Mariner
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Feb 4, 2001
Messages
16,978
Re: 1998 Evinrude 120 compression test

The highest cylinder (top starboard) is #1 and the lowest (bottom port) is #4.<br /><br />Good luck!
 
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Solittle

Fleet Admiral
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Apr 28, 2002
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7,518
Re: 1998 Evinrude 120 compression test

I would put the muffs on and turn the water on very low to lube the impeller. Also pull all the plugs before you start.
 
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ob

Admiral
Joined
Aug 16, 2002
Messages
6,992
Re: 1998 Evinrude 120 compression test

SoLittle,Gives good advice.Nice tip on not running the waterpump dry during cranking.
 
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