My 1989 225 Johnson has an intermittent problem where I'll be cruising
along just fine and then it will miss/drop RPM for a second or two,
then run fine again. Sometimes it does this for a few seconds longer,
but then jumps right back, and other times it keeps dopping and
surging until I either pull back or the boat comes off plane and the
rpm drops to 3500 rpm so wide open. (P.S. I only did this after I was
sure it wasn't fuel starvation)

It usually happens after boat has been run awhile (10-15 minutes if on
the first outing of the day, sooner if the engine is already warm),
but not always, and sometimes the Tach jumps around. Some days I don't
see it at all. I've ruled out the fuel system outside of the motor by
running it on a portable tank w/ a new hose and bulb w/ same problem.
It also is not like the problems I've seen on this and other OB's w/ a
clogged filter, stuck check valve, bad fuel pump, or water in the gas.
I've checked for loose wires, and replaced the spark plugs and wires.

Any help would be appreciated.

FishFan