48-43586-13 merc prop

[hardwater fisherman]

I have a prop that is part number 48-43586-13... I believe the 13 is the pitch.. But there is no diameter stamped on it..It measures around 9 1/4".. It came with a 1994 20hp I have..I was getting around 5200 RPM WOT with this prop... I have since put a 25hp carb on the motor and the RPM went up to 5650-5700 RPM.. I bought a 10 3/8 x 11 prop and it gives me only 5450 RPM... I thought the drop in pitch would give more RPM and not less... So will the smaller diameter offset the pitch? My local shop was not able to find the part number and I can not find out much about the prop... I have seen the number 48-43586A40-13 but it is 10 3/8 diameter...

 

[flyingscott]

Less pitch but bigger blades so less RPM. The 13" pitch prop would have come factory on it so run it your rpms are fine.

 

[hardwater fisherman]

Thanks.. The 11 pitch performs better when the boat is loaded heavier so when alone I will run the 13 pitch..

 

[flyingscott]

Where did you get a a 9.25" diameter prop. The factory prop is 10 3/8 x 13 this is the part # 48-19640A40. I run an 89 version of that motor and that is the prop I have. You may want to make sure the blades have not been chewed off and reshaped.

 

[hardwater fisherman]

The prop came with the motor from a guy with lots of motors. He sells used parts.. So the prop probably came off something else... It appears merc made a 48-43586A20 prop as well., The prop in the photos is not mine but one I saw online.

 

[hardwater fisherman]

This is my prop.. EDIT It may smaller then 9.25" It is slightly larger then a 8 1/2" x 11" piece of paper..The guy at the local shop thought it may be 9.25".. I am not sure how to measure it though.

 

[flyingscott]

It is the right prop you are just not measuring it right. The 10 3/8 is straight across the widest part. If it was a 2 blade prop you would measure across the widest point or tip to tip.

 

[hardwater fisherman]

Okay thanks.. I guess because the 2 props look different and when on the motor the 13 pitch has more "clearance" than the 11".. Or is that due to the pitch and the shape of the blades? Does the 13" pitch look like it is worn down?

 

[hardwater fisherman]

Also you can see by the photos that the hub is quite a bit smaller on the 13" pitch...