Shaft Heating

Sometimes we're our own worst enemies when it comes to causing premature wear on the drive shaft. One of the owners ran the engine exhaust down the shaft to get it farther away from the boat. Sounded like a good idea to me, since it was quieter, but it caused some unforeseen problems. As the exhaust heated up it also heated up the shaft and grease inside. Grease was pushed by the upper and lower seals and when things cooled off, water and silt were sucked in past the lower seals. We figured this out after replacing two shafts for grooves under the seals. When the exhaust was rerouted the problem stopped.