Want to buy new prop and use old one as spare

[ONJames]

Hi All,

I have a 1989 Century 3500lx bowrider 21' with a 5.7 Merc that I bought in October 2012. I'm very new to boating so I bought an old boat to learn on and have learned a lot!
I want to buy a new prop and use my old one as a spare because it is kind of beat up but I cannot figure out what size it is. I'm told the size is in by the prop nut but mine is very corroded in there and there are no numbers to be seen. There is a number engraved on the side of the prop -1918 21-. Does that number mean anything?
Any help would be much appreciated.. I have posted pics of the prop.

Thanks

 

[steelespike]

Re: Want to buy new prop and use old one as spare

I don't recognize that number but does seem like it may be a 21.
Maybe someone will be along that knows the number.
If we knew your lightly loaded wot rpm,gps speed, gear ratio(on the leg)We may be able to tell if a 21 makes sense.
If all else fails a prop shop may be able to tell.

 

[ONJames]

Re: Want to buy new prop and use old one as spare

I snapped this pic last fall with only myself on the boat. View attachment 207621
I don't have a GPS nor do I know the gear ratio. How do I find that out? I have been able to find out very little information on this boat let alone any sort of manual. It has been a great boat and I don't need to change the size of prop, I just want a new one.

 

[jestor68]

Re: Want to buy new prop and use old one as spare

Mercury's size would be a 14.25 X 21.

Solas has a 14-3/10 X 21. Either one will work.