1981 50hp Merc, spun prop hub?

[Dee Rambin]

I was wondering if this year model / size motor used the rubber hubs in the prop? I was running about 3/4 throttle and all of a sudden the engine revved up but speed fell off. It will start to catch at first, but will not get up on plane without the rpm's rising and speed falling off, seems it's getting worse. Any insight will be most appreciated!

 

[KCLOST]

Re: 1981 50hp Merc, spun prop hub?

Pull the prop and you will see...<br /><br />The inner hub will be visible from the back of the prop where the thrust washer goes against it.<br /><br />The year of the motor isn't necessarily the factor, it's the prop itself... Take everything out and inspect...

 

[Barnacle_Bill]

Re: 1981 50hp Merc, spun prop hub?

Those are certainly symptoms of a spun prop. You can check it by making a mark on the inner and outer parts of the prop and take it out for a spin and see if the marks move. Or take it to your local prop man and have it checked.

 

[big_merc]

Re: 1981 50hp Merc, spun prop hub?

yea definitly your hub is spun, my motor did the exact same thing.......

 

[Dee Rambin]

Re: 1981 50hp Merc, spun prop hub?

I love this board, and all the helpful information herein. Thank you all for your help. <br /><br />KCLOST - I really am trying to get that #%$% prop off, it's stuck like chuck. The boat had been sitting up for 6 years due to a frozen steering cable (which I was able to replace with a lot of help from this board). I am currently soaking it in penetrant with hopes to break it free after reading posts here regarding the same problem.

 

[KCLOST]

Re: 1981 50hp Merc, spun prop hub?

I see!!!! <br /><br />Good start using the penetrant... Keep at it.. And don't horse it too much don't want to harm the gears...

 

[andrewkafp]

Re: 1981 50hp Merc, spun prop hub?

Hindsight is a great tool... but when and if you do get it off.. make sure you periodically remove it and grease the splines in the future and use a new tab washer.

 

[KCLOST]

Re: 1981 50hp Merc, spun prop hub?

If you don't mind sacrificing the prop you can make it easier... (it might tear up the prop anyway depending on how things go, you will at the best end up with three holes in the the prop hub, which which you may be able to plug later). Not real easy but a way to at least make it quick I guess...<br /><br />You can,,,,,Try a flywheel puller of the appropriate size.. but you will have to drill holes in the outer hub of the prop to have something for the puller to grab on to, I've heard of this, but haven't tried it myself, and you may warp the prop especially if it's aluminum, you will have to tap on the prop as you gradually tighten the puller......This won't harm the gears however...<br /><br />Thought I would mention it, but the worse part may be finding a puller that will fit.. It's a game of making the puller fit and still being able to apply force to the prop shaft..