Nissan props

[iggyw1]

I have a 70 H.P. Nissan outboard 1991 model. I have a prop on it that works great, but I want to get another one. All I see on the prop is one number, and it's a 12 inside a circle on the hub of the prop. Is this the diameter or the pitch?

Also, I seen and ad local to me on Craigslist that someone is selling a prop from a Mercury motor. He says it has 13 splines on it (same is my prop on my Nissan). His prop is also a thru prop discharge, same as the Nissan. I don't know the pitch or the size, but if it fits on my shaft o.k., is it alright to use it even if the diameter is bigger or smaller?? I see Nissan props listed for my motor that have different diameters as well. Do all motors use a variety of diameters as they do pitches?

 

[Sea Rider]

The diameter is all about what the prop manufacturer want to play with, pitch is more important. Why buy a second if don't know if the current one performs top for your boating needs and revs the motor to at least middle to max wot rpm range which should be 5800 revs. Does the boat counts with an installed tach in excellent working order ?

Happy Boating

 

[iggyw1]

My max is 5800 PM's. My motor revs at between 5500 to 5800, depending on my load and other variables. I should have said in my post that I want to get another prop just so I have a spare prop that will get me back in if I should bust a prop on something out in he lake. I heard a lot about the pitch but I never read or heard nothing about the diameter. Do you know what the 12 in a circle represents on my Nissan prop? And again, IF the Mercury prop fits the prop shaft , and the diameter clears everything, that would be o.k. to use, correct?

 

[km1125]

If there's just a single number stamped on the prop, it's the pitch. You can just measure the diameter by measuring from the center to the tips of the blades and doubling that. The craigslist prop will also have a pitch stamped or cast on it somewhere, they just need to send you some good pictures that show it.

Yes, if it fits the splines and the diameter is not so big that it strikes the ventilation plate or anything else, it will work but it may not give you anywhere near normal performance if the pitch and/or diameter are very far off. But it will get you back to the dock.

 

[Sea Rider]

Don't know if a Merc prop will fit or work same, there could be rpm variations due to design, blade shape, etc, but a 70 HP OEM Tohatsu prop will. Nissans are rebadged Tohatsu versions. In that case buy same prop pitch to count with a spare prop.

Happy Boating

 

[pvanv]

There are 3 props still available, ranging from 12 to 17 pitch.

 

[iggyw1]

O.K. Thanks to all of you. I will take my boat with me after taking my prop off and make sure the Merc prop fits the shaft o.k. when I go to check it out. It's gonna be a spare unless it performs better than my Nissan prop for some reason. (My boat is on a trailer).

 

[Sea Rider]

O.K. Thanks to all of you. I will take my boat with me after taking my prop off and make sure the Merc prop fits the shaft o.k. when I go to check it out. It's gonna be a spare unless it performs better than my Nissan prop for some reason. (My boat is on a trailer).

OK just for the record, report the max wot rpm achieved as usually loaded on flat calm water cond with Merc prop...

Happy Boating