i have 1968 120hp, 153cid, 2.5L Mercruiser and went i check the oil was ok then i take to the bay above 35 min. off shore then the lifters start sounding little bit and in the way back 35 min. more run fine but at the dock i notice the lifter sounding again i get the boat out and go home for the day but went i was washing the boat i check the oil and needs above 3 qts i using what mercruiser recommend 25/40 oil. <br />no smoke and the bilge is clean and dry unless the eng. was not completed level went i do the ck the oil first time; i going fishing to the same place on Saturday i going to be shure that the boat is level and the oil is at the line.<br /><br />i forget to mention that went the lifter start sounding the pressure lower from 40 to 20.<br /><br />I do a second test. I drive 12 miles at 3500 rpm speed (20 mph GPS) then i stop the engine because lifter start sounding and when i check the oil was 1/4 and 1/2 low put some oil on and drive back 12 miles to the shore at 3500 rpm (20 mph GPS) when i get to shore take the boat out check the oil and was 1/4 and 1/2 low.<br /><br />the oil pressure go down and the lifter sound when the oil level drop one qt and i think has to be some sign of oil thru the exaust if the eng. burn oil.?<br /><br />i check the plugs, boot, pvc and they are fine what i find was some oil on the water hoses and in the valve cover filler cap was muggy i was thinking above small crack in a cilinder block (no water in the oil pan) i don't have oil cooler sys, new head gasket and head resurface and (check for crack)that what the machine shop said he do.. what do you think.? <br /><br />i also check with the match to light the oil stick and was neg.
