TOPIC: cause of low compression

cause of low compression 5 years 18 hours ago #141423

63 Sabre Topic Author Offline Contributing Member Posts: 4676 Karma: 147 Thank you received: 167	Looking at a '77 Evinrude 140hp but has low compression in all four cylinders, 75.80.etc. What would cause this to be in all four? Maybe running with no mix? Over heat and warped heads?. Can get it really cheap with working tnt. Everything else is good. Opins please. Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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jimandros Offline Gold Boarder Posts: 651 Karma: 76 Thank you received: 37	OMC never publicized compression. Only that they should be within 10% Cold engine, no back pressure & large exhaust ports will all cause low compression at cranking speeds. My old 90 DU only reads 60 or so. Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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63 Sabre Topic Author Offline Contributing Member Posts: 4676 Karma: 147 Thank you received: 167	Thanks, Now I'll probably get another motor to hang on the wall. Nothing like having an over powered backup for a 15 footer. Check this box to be notified of replies to this topic. Note: BBcode and smileys are still usable.
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