ok guys check this out, i have a 1986 mercruiser 140, alpha 1 combo, it wasnt running great last week so i gave it a tune up, all filters, oil, ignition parts, ect. started it up and it still had a miss in it. i checked timing, vacuumm, still with no results, so i took it to the local marine mechanic, he looks at it and decided to do a compresion check, here are the results, <br />#1 120<br />#2 120<br />#3 120<br />#4 120<br />this is the wierd part, if you hook up the ignition while doing the compresion test it starts to run at a higher rpm than if you were just cranking it over. the compresion in the #1 cyl drops to 80 psi, so he thinks the valve may be adjusted to tight. when the rpms pick up, the oil pressure increases and causes that lifter to pump up, causing the valve not to seat, does this seem possible, by the way the motor did run great last season..i find it hard to beleive that a nut on a rocker arm can tighten on its own. what do you guys think?
