96 merc 200efi

[SCastillo1368]

When I Start Fishing, Motor Starts Good, Runs. I Can Stop 4 Or Five Times, And It Will Start Right Up. These Are All Short Runs. If I Take A Long Ride And Stop The Motor And Try To Restart It, It Won' Do Nothing. When I Put It Back On The Trailer, It Will Start Right Up. Please Held.

[boats.net]

When you say "It Won' Do Nothing" if you mean the starter wont crank engine over then check battery cables and connections, neutral safety switch and key switch. If engine wont run then check for spark at plugs, check fuel pressure at fuel rails.