Place the scallops in a shallow 8 X 8-inch baking dish.
Combine the lemon juice, tamari, pineapple juice, and oil in a small bowl and pour over the scallops.
Refrigerate for several hours or overnight.
Cut the stems off the mushrooms close to the caps.
Steam the mushrooms and peppers for 2 minutes.
Rinse under cold water until cooled.
To prepare the kabobs, place the mushrooms, peppers, pineapple, and scallops alternately on metal skewers.
Set over a grill or under the broiler until the scallops are opaque and firm throughout, 3 to 5 minutes.
Do not overcook.