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OMC compression test question

A

alan

Contributing Member
" I want to test the compressi

" I want to test the compression for my 1985 Johnson 120 looper. What is the procedure to get the most accurate reading(s).

Do I have to remove the accelerator/gas cable ? What are the readings I should expect for a healthy motor ? Within what paramters ?

Thx,

Alan "
 
Throttle position does not ma

Throttle position does not matter on a two stroke . Compression starts after exhaust ports close.
 
"The proper procedure from Joh

"The proper procedure from Johnson/Evinrude is
perate engine to normal operating temp.stop engine.Remove ALL spark plugs.Install a thread-in
compression tester,FULLY charged batt,throttle WIDE OPEN,crank at least 4 compression strokes,
lowest cyl should be at least 80% of highest cyl.
ZEKE @ ZEKE'S MARINE SERVICE JUPITER,FLA.
[email protected]"
 
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