Outboard vs. Sterndrive props-Is there a difference?

[kneedragger]

Here is my question. I just purchased a used '94 Rinker with a 4.3L LX with a Gen 2 outdrive with ser # 0F31442.

I have experience with two-smoke outboards, but haven't owned an in-out since the late 80's when I was a freshman in college.

My prop is in need of refurbishment, and or replacement. It is showing signs where it has been refurbished in the past.

I would like to purchase used if possible(because that is all the budget will allow), and want to know what the stamped numbers on my prop mean.

48 78120A40 19P. How do I tell the diameter? I know it is 19" pitch, but will an outboard prop work just as well? It seems that the spline shaft on the lower unit should be close to the same.

Granted I do not plan to put a 50HP outboard prop on my 190 HP outdrive.

Thanks in advance for the help.

 

[Gary H NC]

Re: Outboard vs. Sterndrive props-Is there a difference?

Use the prop finder feature here in the Iboats store. It will give you many different 19 pitch props to choose from.
Aluminum is not that expensive if your on a budget.

A new Solas is under 100 bucks
http://boatpropellers.iboats.com/Me...r=1994&**********=425051394&*******=507416854

 

[MikDee]

Re: Outboard vs. Sterndrive props-Is there a difference?

Usually an I/O prop is larger in diameter, and sometimes has more wetted area.

 

[Dhadley]

Re: Outboard vs. Sterndrive props-Is there a difference?

There are props made for both and props made specifically for one or the other. Props made to run at higher X dimensions are generally intended to be run on outboards since the X dimension is easily changed. A lot has to do with hull design as to which prop is best for your application.

 

[kneedragger]

Re: Outboard vs. Sterndrive props-Is there a difference?

I would like to purchase used if possible(because that is all the budget will allow), and want to know what the stamped numbers on my prop mean.

48 78120A40 19P. How do I tell the diameter? I know it is 19" pitch, but will an outboard prop work just as well? It seems that the spline shaft on the lower unit should be close to the same.

Thanks for the responses, However the above questions still remain. What do the numbers on the prop represent?, How can I determine the diameter of what I currently have, and will the splines cross over from an outboard to an inboard?

 

[Silvertip]

Re: Outboard vs. Sterndrive props-Is there a difference?

The numbers on the prop can mean a number of things depending on manufacturer. In your example, that's a Mercury part number, which your dealer or you would use to order an exact new replacement from Mercury. That number becomes useless (except for cross reference purposes) to anyone else because their props are not numbered that way and the numbers don't actually translate to anything (except for the 19P which is 19 pitch). Technically, that part number refers to the top assembly drawing that defines how the prop is made. A description in the parts list merely lists the part number, identifies it as a xx diameter, 19P prop. You can key that part number into a Google search and it should turn up basic diameter and pitch but there is an easier way to determine this. Measure it! On a three blade prop, measure from blade tip to the exact center of the hub and multiply by 2. On a two or four blade, measure across opposite blade tips. You cannot however, measure pitch. Props from other manufacturers have different ID's. A model Code may be used or some other part number may be used. Or the prop may simply be marked 12-2/4 x 17P or similar marking depending on size.

 

[Tail_Gunner]

Re: Outboard vs. Sterndrive props-Is there a difference?

Thanks for the responses, However the above questions still remain. What do the numbers on the prop represent?, How can I determine the diameter of what I currently have, and will the splines cross over from an outboard to an inboard?

There is very little chance that your old prop will fit on your I/O. Both the splines and the diameter will be different. As to diameter of the prop you want it to match the lower gear case...where the prop is mounted on the leg.....If your gear case is larger than the prop diameter or smaller than the prop diameter it will cause a distrubance in the flow of water to the prop resulting in slip.

Not to much can be done with a I/O's and props, other than getting a prop that runs or turns a boat at the max rpm the motor is designed to run at......

Three blade props will run faster @ WOt than Four blades....Four blades will generally have more midrange punch and lower planing speeds. There are props that provide Bow lift or Stern lift..

You will have to decide..is your boat Bow heavy or Stern heavy. Do you want abolute top speed performance that would be a 3 blade design.....4 blades as said above will give you a lower planing speed and increased midrange response.

aluminum... good prop's and good performance... SS will enhance all of the above....The adventure is the real fun...

 

[kneedragger]

Re: Outboard vs. Sterndrive props-Is there a difference?

Thanks so much Tail and Silvertip!

This helps me out a great deal. If I have further questions I intend to post.

Thanks,

 

[Bondo]

Re: Outboard vs. Sterndrive props-Is there a difference?

but will an outboard prop work just as well? It seems that the spline shaft on the lower unit should be close to the same.

Granted I do not plan to put a 50HP outboard prop on my 190 HP outdrive.

Ayuh,.... The prop from a 50hp, just Won't Fit....
But,...
What I've found is that the props for the Large Gearcase(4, 1/2") Outboards, are the Same sizes as the Mercruiser Mod.1s, Pre-Alphas, Alphas, including the Gen.IIs,+ the Bravo 1s....
That only means it'll bolt on,+ fit,....
Wherther the blade configuration is what you need is something different,...
The prop Hubs are the same....

 

[180shabah]

Re: Outboard vs. Sterndrive props-Is there a difference?

I sound like a broken record today, but if you are looking for a cheap performance propeller - look no further than a Hustler. Get the same pitch you have now and don't get hung up on the diameter.