2003 Yamaha 50hp 2 stroke outboard
I changed my lower unit oil and since then it's been leaking out onto the inside of the prop. This didn't happen before I changed the oil. I think I know how it happened, but am looking to pick some brains out there to see if I'm correct.
When I removed the oil pump from the bottom hole, oil started coming out pretty quick before I could get the screw in.
This happened even though I had already replaced the top screw prior to removing the oil pump. I figured I could just add a little more oil through the top hole to replace the oil I lost while trying to get the bottom screw in. I suspect that when I pumped oil into the top hole, the pressure created in the lower unit may have dislodged one or both of the two oil seals on the prop shaft.
My question is two-fold... first, does my idea of what happened sound realistic?
Second, how do I know the other two oil seal locations aren't leaking, too? The other two are on the driveshaft and on the shifter rod. I have a theory about this also, but would like to know if anyone knows for sure. My theory is that Yamaha purposely makes the prop oil seals the weakest link, so that they blow out before the others. They would do this because it's a lot easier to change the ones on the prop shaft than having to remove the lower unit to access the others.
I do realize that all of these oil seals are the same, so I know Yamaha didn't make some weaker than others. But according to the manual, the oil seals on the prop shaft have a lot more room to give than the other seals. I believe the ones on the prop shaft can pop out approx. 4mm, whereas the others can only pop out approx. 1mm.
If unexpected pressure occurred in the lower unit, the prop shaft oil seals would be the likely failure.
Does anyone have first hand experience with this enough to be able to confirm or deny any of my assumptions?
Thanks!
I changed my lower unit oil and since then it's been leaking out onto the inside of the prop. This didn't happen before I changed the oil. I think I know how it happened, but am looking to pick some brains out there to see if I'm correct.
When I removed the oil pump from the bottom hole, oil started coming out pretty quick before I could get the screw in.
This happened even though I had already replaced the top screw prior to removing the oil pump. I figured I could just add a little more oil through the top hole to replace the oil I lost while trying to get the bottom screw in. I suspect that when I pumped oil into the top hole, the pressure created in the lower unit may have dislodged one or both of the two oil seals on the prop shaft.
My question is two-fold... first, does my idea of what happened sound realistic?
Second, how do I know the other two oil seal locations aren't leaking, too? The other two are on the driveshaft and on the shifter rod. I have a theory about this also, but would like to know if anyone knows for sure. My theory is that Yamaha purposely makes the prop oil seals the weakest link, so that they blow out before the others. They would do this because it's a lot easier to change the ones on the prop shaft than having to remove the lower unit to access the others.
I do realize that all of these oil seals are the same, so I know Yamaha didn't make some weaker than others. But according to the manual, the oil seals on the prop shaft have a lot more room to give than the other seals. I believe the ones on the prop shaft can pop out approx. 4mm, whereas the others can only pop out approx. 1mm.
If unexpected pressure occurred in the lower unit, the prop shaft oil seals would be the likely failure.
Does anyone have first hand experience with this enough to be able to confirm or deny any of my assumptions?
Thanks!