Home › Forum › Ask A Member › Driveshaft water tubes, 18-35hp motors › Re: Driveshaft water tubes, 18-35hp motors
on the 18-35hp motors (old and new), they use a water tube on top of the impeller housing to create a shield from exhaust pulses entering via tiny holes atop the housing. Both styles use 2 o-rings at each end of the tube to seal it up. I’m assuming this creates a water seal up the driveshaft housing, and if this o-ring at the top of the driveshaft is missing, allows water to work its way up into the drive/crankshaft articulation/splines.
The 9.9/15 upper driveshaft bearing housing (for lack of a better term) has a couple of other seals too. They don’t have a water tube like the larger HP motors, but this one (pictured) was seized up with salt up there.