1985 Bayliner Capri OMC Series 800 - In forward gear it has a slight,
intermittent, "bump". It's not the "slipping out of gear at high RPM's
and then slams back into gear", but it does seem like it slips out of
gear for just a split second. Happens at all RPMs. Has never happened
in reverse. The shifting is not "one finger" smooth into and out of
gear, but it's not excessively hard either.

We started with upper and lower seal kits as both had water in the
oil. Mechanic found broken impeller on water pump so we replaced the
wp and wp shaft. He also found a crack in the upper gear case housing,
but he welded and it now holds pressure. No luck with the "bump"
problem.

Next was a complete tear down of the lower unit gears. There was some
wear but no broken teeth. Regardless, given the prior seal problem we
replaced the lower unit gear set (for, rev, c.dog, pinion, and shaft
bearing). Mech mentioned some linkage damage due to "dry shifting"
that he "filed"? (I didn't understand this part). The "bump" is still
present but less frequent.

Mechanic has now suggested replacing the upper unit gear case housing
as the prior crack and weld may have distorted the shape and there may
be some slop in the fittings of gears and shafts.

After reading many comments on this board I'm now wondering about the
shift cables. Is the little "bump" that I get a precursor to "slipping
out of gear and slamming back at high RPM's?" Any other suggestions?