Identifying If Your Engine Is Equipped With Exhaust Spacers
The installed exhaust height is crucial to the longevity of the marine engine. Without proper compliance water will quickly enter the marine engine through the marine exhaust system causing catastophic engine damage. The purpose of the exhaust height specification is to ensure that an air break exists at some point in the marine exhaust system. You can think of it as the exact opposite of a P-Trap in your sink.
Regarding the proper height for the marine exhaust system this will vary by manufacturer. Mercruiser for example requires 13" minimum from the top of the exhaust elbow to the water line measured with the boat at rest in the water. Therefore if you have a deep V boat the engines will typically sit lower in the hull and therefore may require the use of spacers to get the exhaust elbow in compliance with this minimum height dimension. Select the following link to see how to verify if your exhaust height is correct. Read More…
The following image illustrates both types of exhaust marine system; one without exhaust spacers while the other shows a 3" spacer. The most common sizes for the exhaust spacers range from 3" to 6".
