- 1). Bolt on a vertical-exhaust rain cap, available at tractor supply stores, truck stops or some auto stores. Measure the length across the top for the correct size, then place the cap on the top of the stack and tighten the clamp to hold it on securely.
- 2). Compress an old rag in your hands and insert it into the exhaust stack. Wrap duct tape over the top of the stack and inserted rag, using scissors to cut the tape to an approximate length of about 6 inches. Cut several strips of tape to securely cover the rag inside the stack, while pressing the tape firmly in place for a tight seal.
- 3). Cover the exhaust stack with a common plastic grocery bag, then wrap duct tape over the plastic to secure it in place. Wrap some duct tape horizontally over the pipe to cover all of the plastic for a water-tight seal.
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