Prop shaft seals?

[Jon1229]

Hi all,

when I pulled my boat in the fall I drained the lower unit and there was a bit of water in the gear case. I hit bottom pretty good at one point in the year and I’m thinking that is when water started to come in. Before the season all seals were replaced, so I don’t think it would be one of the upper seals. On the diagram, it shows an inner seal and an outer seal on the prop shaft, which would be the one, if not both to replace? Am I right for thinking it is likely one of those two? It is a 2001 mercury 150 saltwater series. Serial 0T266256.

Thanks for any input!

 

[roscoe]

Did you hit bottom with the skeg/gearcase, or the prop?

If you hit with the prop, it could have bent the shaft and possible caused the leak. Might be a good idea to have the shaft checked out.

I, my opinion, if the shaft is good, then it is more likely that the fill/vent screw gaskets are leaking. Or one of the seals was damaged when installed last year.

 

[Texasmark]

Checking the shaft isn't hard to do. A quick check is to remove the prop and using a ruler, at the tip of the prop shaft is a dimple where it was milled on a lathe during mfgr. Using your tongue jack on your trailer adjust the lower unit off the floor a comfortable distance. from the rear, you lying on your side on the floor (creeper) with an accurate ruler, caliper, with the engine in N, rotate the prop shaft with one hand while holding the ruler with the other. That will answer that question.

Course it could be that it's just time to do it based on age and usage. The seals are back to back in that the outer keeps water out so it's facing in that direction but the inner is to keep oil in....so it's facing the opposite direction.

You don't have to remove the bearing carrier to get at the seals. Get a suitable sized drill bit and a pair of # 6 or 8 sheet metal screws. Drill a pair of holes in opposite sides of the seal. Grasp the screws and pull the seal out. A sliding seal/wheel puller tool will make the job easier...Harbor Freight has them cheap, or rig up something to pry them out.

Installation of the new one should have a thread sealer applied to the metal to metal sealing surfaces per the serv. manual who recommend red and remember to pay attention to the direction of the lips.

 

[Jon1229]

Did you hit bottom with the skeg/gearcase, or the prop?

If you hit with the prop, it could have bent the shaft and possible caused the leak. Might be a good idea to have the shaft checked out.

I, my opinion, if the shaft is good, then it is more likely that the fill/vent screw gaskets are leaking. Or one of the seals was damaged when installed last year.

My prop hit the sand, I was actually going in reverse when it happened. I’ll be sure to check the shaft before making any decisions. Thanks!

 

[Jon1229]

Checking the shaft isn't hard to do. A quick check is to remove the prop and using a ruler, at the tip of the prop shaft is a dimple where it was milled on a lathe during mfgr. Using your tongue jack on your trailer adjust the lower unit off the floor a comfortable distance. from the rear, you lying on your side on the floor (creeper) with an accurate ruler, caliper, with the engine in N, rotate the prop shaft with one hand while holding the ruler with the other. That will answer that question.

Course it could be that it's just time to do it based on age and usage. The seals are back to back in that the outer keeps water out so it's facing in that direction but the inner is to keep oil in....so it's facing the opposite direction.

You don't have to remove the bearing carrier to get at the seals. Get a suitable sized drill bit and a pair of # 6 or 8 sheet metal screws. Drill a pair of holes in opposite sides of the seal. Grasp the screws and pull the seal out. A sliding seal/wheel puller tool will make the job easier...Harbor Freight has them cheap, or rig up something to pry them out.

Installation of the new one should have a thread sealer applied to the metal to metal sealing surfaces per the serv. manual who recommend red and remember to pay attention to the direction of the lips.

Thanks for the reply. That’s certainly much easier of a process than pulling the carrier. Keeping my fingers crossed!

 

[Jon1229]

Okay, so my prop shaft is slightly bent, what are my options going forward?

 

[racerone]

Some folks have insurance to help cover the cost of hitting --rock bottom----Still expensive.-------Your local shops may be interested in straightening the shaft.