Prop shaft play, normal or abnormal?

[austin123]

Mercruiser Alpha One. Serial #OB890142.<br /><br />I have the unit out replacing the water pump and painting the outside of the unit. I posted a question about the prop scraping when installed but did not get a reply.<br /><br />After closer inspection I notices that the rear outer edge (circumference) of the prop is lightly touching the retaining nut when installed. I also noticed that none of the tabs are bent into position to lock the nut in place?<br /><br />When I push and pull on the prop shaft (without prop installed) I can get about a 1/8 total movement. Is this normal? <br /><br />I could try to lock the nut down more to see if it has been torqued to the correct value (150 ft/lbs I believe) but do not have the tool.<br /><br />I do have the thrust hub in place.<br /><br />If the play in the shaft is normal can I just remove a small amout of material off the back edge/circumference of the prop?<br /><br />Thanks for any input,<br /><br />Austin.

 

[rodbolt]

Re: Prop shaft play, normal or abnormal?

hello<br /> the alpha genII has a lot of endplay. they also use a shaft thrust washer to limit it. sometimes it gets left out. on the prop scraping the cover I would suspect the incorrect thrust washer or missing thrust washer.<br /> I see it all the time.<br /> good luck and keep posting

 

[austin123]

Re: Prop shaft play, normal or abnormal?

Is there a standard thrust washer or different ones for different props?

 

[Bondo]

Re: Prop shaft play, normal or abnormal?

When I push and pull on the prop shaft (without prop installed) I can get about a 1/8 total movement. Is this normal?

YES......<br />Unnerving, But the way it's Supposed to be.......<br />

Is there a standard thrust washer or different ones for different props?

Lot's of Different 1s......<br />Almost as many,<br />As Different Props........

 

[austin123]

Re: Prop shaft play, normal or abnormal?

What about shimming the thrust washer out slightly or making a slightly thicker one?

 

[rodbolt]

Re: Prop shaft play, normal or abnormal?

hello<br /> maybe I was confusing.<br /> the propshaft has 2 thrust washers. one is inside the unit and controls endplay and is non adjustable and also helps give the reverse gear face a thrust surface.<br /> the prop thrust washer goes on the shaft just forward of the prop, the taper on the prop shaft mates with the taper of the prop thrust washer. the prop tranfers foward thrust to the prop shft by this washer. if the wrong one is used for the prop you have then it can cause all sorts of problems.<br /> good luck and keep posting

 

[rodbolt]

Re: Prop shaft play, normal or abnormal?

hello<br /> a PS<br /> if you have an alpha one it does not have the shaft washer in the case just the genII had them. all have the prop thrust washer

 

[russdrussd]

Re: Prop shaft play, normal or abnormal?

Hello,<br />I have the same problem as you describe with my new Laser II Merc prop (including new installation hardware) scraping the retaining nut. Please let me know if you found a prop thrush washer that worked for you and the part number.<br /><br />Thanks