I have a 1992 Malibu EuroF3Skier with a 5.7L Competition Ski -Serial #OD385341 that has a sticky lifter. The lifter in question is on the passenger side at the front. The noise only occurrs after pulling a skier or running the boat for a while. Upon detecting the noise at idle, reving the motor up resolves the noise. These boats have the motor on angle - approx. 8 degrees as they are direct drive and the shaft exists thru the hull approx. two feet from the transom. The lifter in question is at the highest point so my initial concern was lack of oil. I had a oil pressure test done and the reading was 40 lbs. at idle when first started - ie. cold. After ruling that out I ran an oil flush using a B&G product and then drained and refilled the oil and replaced the filter. The lifter noise went away for the past three years. The motor gets approx. 40 hours of use per season and has a total of 390 hours (when first detected 270 hours). I use a B&G oil additive (Engine MOA) which I have had good success with. The engine only gets Mercruiser 25W-40 oil and filter. The noise has reappeared on the same lifter. I'm struggling with why the oil should need flushing again. Should I be replacing the lifter as I can not see how the oil is dirty already.
