To amplify Jim's answer: He is referring to the intermediate shift cable
that goes from the shift trunnion mounted on the engine out to the stern
drive mounting housing.
When this cable starts to go bad it starts to bind. That causes the
ignition interrupter switch to activate prematurely. As a result, the
ignition is shut off too long - shutting off the engine.
The switch's function, when operating properly, is to temporarily shut
off the ignition, unloading the pressure on the gears. When the pressure
is relieved it is much easier to shift.

Good luck and good boating,
Jim

Jim wrote:
You probably have a bad shift cable.
Jim
"eko3" wrote in message
ups.com...

I have a 140 hp merc that has always started and ran perfect. Last week
it started dying when I decelerated or shifted into nuetral. It still
runs fine if I can get out of nuetral and into gear before it dies I
replaced both fuel filters, plugs and points and it still dies when I
shift to nuetral. ANyone have an idea what could be causing this.