Prop selection puzzle

[Moody Blue]

1992 Mariner 40HP Magnum currently has 10 1/8" dia 3 blade prop. Unsure of pitch as there is no marking anywhere on it. It does have cupped blades. Am trying to buy a spare/replacement prop but am confused by the listings here on iboats. If I enter the parameters in the selection windows I end up with 13" dia props as the choices. If I enter 25hp in the selection windows I end up with the 10" dia props. What do I do ??? Does the motor have the wrong prop on it ? Have recently bought a tach to install this spring so I have no idea what the motor was running at with the existing prop. The motor is on a 14ft f/g whaler style boat that weighs about 550Ib's including motor if that has any bearing on the selection. Are there other sources of reference to determine the correct prop ? I should mention that there seems to be room to fit a larger prop (13" ?).

 

[Moody Blue]

Re: Prop selection puzzle

Forgot to mention that the prop shaft has 13 splines but the iboats choices for the 40hp props indicates 15 splines. Now I am really confused.

 

[rabidfish]

Re: Prop selection puzzle

The only prop made by Mercury for that engine, that had a 10 1/8 diameter was the 15 pitch.<br /><br />Mercury part # 48-73140A40<br /><br />It fits th 2-stroke 40 - 50 hp(classic)<br />It fits the 25 4-stroke bigfoot<br />and the 30 - 40 4 stroke also.

 

[Barnacle_Bill]

Re: Prop selection puzzle

Wait until you get the tach installed and then let us know what your WOT is.

 

[Dhadley]

Re: Prop selection puzzle

I have several ss props in that configuration. When youre ready I'm sure we can get you going.