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'93 Johnson 25HP, Can't get it to idle right...VIDEO!!
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<blockquote data-quote="double5" data-source="post: 474357" data-attributes="member: 24734"><p>As has been indicated on this thread, a leaky crankcase seal can lead to lack of "pre-compression". Two strokes pressurize the crank case on the downward piston stroke so that it can be taken into the intake port and ignited on the upward stroke (where your "normal" compression test reads"). You can use soapy water sprayed on the outside of the case, upper seal etc. and monitor while cranking. I would do it with the ignition disabled. If all is good, the reply about the lower seal could be it and it would require the powerhead removal to test that. That stuff has driven me crazy before and that is the only reason I am a bit familiar with it. Do all that after checking the idle adjustment etc.</p><p></p><p>Hope that helps.</p><p>Jeff in GA</p></blockquote><p></p>
[QUOTE="double5, post: 474357, member: 24734"] As has been indicated on this thread, a leaky crankcase seal can lead to lack of "pre-compression". Two strokes pressurize the crank case on the downward piston stroke so that it can be taken into the intake port and ignited on the upward stroke (where your "normal" compression test reads"). You can use soapy water sprayed on the outside of the case, upper seal etc. and monitor while cranking. I would do it with the ignition disabled. If all is good, the reply about the lower seal could be it and it would require the powerhead removal to test that. That stuff has driven me crazy before and that is the only reason I am a bit familiar with it. Do all that after checking the idle adjustment etc. Hope that helps. Jeff in GA [/QUOTE]
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'93 Johnson 25HP, Can't get it to idle right...VIDEO!!
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