Mumbles wrote:If you try installing an early shaft with an O ring on it thru the later double seals, you'll know right away something isn't right as the O ring doesn't want to fit thru the small lower seal very easily. I've been caught on this before and it would take a big grunt to get the O ring thru the seal! If I remember correctly, the lip on the lower seal faces out, towards the water pump, to keep water and exhaust out while the lip on the larger upper seal faces in to keep crankcase pressure/vacuum where it should be.
If that seals lower lip faced down, wouldn't it get smashed and messed up by trying to fit the end of the driveshaft through the seal when installing the driveshaft while installing the LU. I had assumed that seal lip would face up. I do see and agree with Mumbles reasoning for the seal to face down keeping the water and exhaust out. There is a bevel on the top of the driveshaft, must be enough to let the shaft enter through the seal. Wish i had taken a look at the seals when i had the powerhead off my '89 9.9 and made a note of the seals orientation.
Good info here!
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