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Spun Hub :( When to replace shaft seal?

A

ahu

New member
Ran the boat over 120 miles the other day after replacing thermostats and bypass relief valve. Had an overheat problem prior to replacing work that would occur over 42-4500 rpm. Glad to say no overheating issues this time. Ran great and smooth and held 4500rpm for 5 minutes or so before backing down to crusing rpm 3900-4100. When I was almost back to the harbor entrance I decided to go WOT and see how she held up and got my boat to hit 40mph at 5300rpm. (19 ft center console with BF150) HOWEVER during the WOT to the harbor entrance the boat lost all power but rpms stayed the same. Immediately pulled back throttle went into neutral and shut off motor. Trimmed all the way up and prop was still there..thank god.. but there was black tar stuff all over the castle nut and cotter pin.. Limped back to dock doing a max of 3.8mph. Pulled prop at home and rubber was melted in hub.
7E43AD91-0465-479C-9642-415F72888A38.jpeg

after pulling prop and thrust washer I took a look at the shaft seal and was wondering when to replace. I’m not experiencing any leaking. I just changed my lower unit gear case oil. This is what the seal looks like
90BB81F7-DBEF-4181-A19D-0B6B2CD3A0E8.jpeg

lastly what is the correct order of parts when putting prop back on.. is it thrust washer.. then prop.. then reverse thrust washer.. then castle nut.. tried finding a picture online and couldn’t find one and I dont have a manual.
 
Hi ahu,

As a general rule, you would be best off to adhere to the old adage "if it ain't broke, don't fix it" when it comes to replacing the prop shaft seal. I don't think there is any recommended service interval for doing that work unless there is a leak. And ideally, if leakage is detected at the gearcase, a pressure and vacuum test should be performed after any seal replacements are done. Something even many so called "outboard shops" can't competently do.

In the parts link below you will see that there are two shaft seals (items 26) "stacked" against each other to provide a degree of redundancy.

https://www.boats.net/catalog/honda...1299999/propeller-shaft-propeller-la-lc-xa-xc

You have the order of the thrust washer (14), the prop (11), the washer (16) and the castle nut (13) listed correctly as is seen in the drawing.

Additionally I will add that the thrust washer orientation is important too with the widest flat going against the gearcase. That flat should be smooth and the thrust washer should be replaced if it has any ridges worn into it.

I don't have a manual for the 150 either but I suggest that little to no torque be applied to the castle nut during install. I believe about 24 in. lbs. is about maximum. I have always had good luck going in finger tight and then to the first available slot to line up the cotter pin hole. It falls under...if you are going to make a mistake, make it too loose not too tight.

On lakes I have found that monofilimant fishing line wrapped around the propshaft is a seal killer. Taking the prop off frequently and keeping line off the shaft is a good practice that also allows for inspecting the hub for signs of failure. Your recent experience is why many boaters carry spare props.

Good luck.
 
What you want to watch for is a bunch of fishing line wrapped around the prop shaft, between the seal and the prop. That can take out a seal in pretty short order.

I always suggest pulling the prop once annually (I do it in the fall). While off, check for the fishing line, and grease the splines on the prop shaft. Some will just ignore this step - until they stick a prop on that shaft and deal with that. From then on, pulling it annually will seem pretty easy....
 
Yes, remove propeller, inspect shaft and seal, grease splines and apply grease to the seal (that will prevent water contact with seal).
That way you will avoid potential future trouble.
 
Heligeorge said:
Yes, remove propeller, inspect shaft and seal, grease splines and apply grease to the seal (that will prevent water contact with seal).
That way you will avoid potential future trouble.
Click to expand...


any grease you guys recommend? It currently has brown grease on it (not sure what kind) But I have some Mercury 2-4-C would that be fine?
 
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