Odds are it didnt come with a prop from the factory, unless it was purchased with a boat size in mind. If it were to go on a Pontoon, it may run a 13 pitch, or if a glass 16ft boat maybe a 17 pitch. Need more info, on boat size, and style. The "read this first" in this section is there for a reason. What are you trying to correct, or do.
Also a ,13x17, and a 13x19, are both 13inch diameter props. You would be more interested in the pitch, over the diameter.
Hello, new at this. We have a 1990 Fisher 240 DLX with A 1990, 90 HP MERCURY. IT'S 24' Long, wieghs about 2400 lbs loaded, the prop is a 13p and all I can get out of it is about 3200 rpm, it runs about 20.5 mph. I've called Tracker and the guy I talked to wasn't much help. Does this sound about right? Just received info on TAP Fins, nice but kind of pricey. Any info would be great. Thanks in advance...
Using a 2.30 gear ratio
4500 produces about 31 with a 19" prop. Gps speed would help. Some cells have a gps app.
It is possible you do need a 17" prop but it will only add about 400 rpm.
You may want to confirm the tach.The problem is in this case you normally wouldn't make up 1000 rpm with a prop.
That would put you at about a 14" pitch.close to what a pontoon would need.
So either the numbers are off or the motor is lacking power.
I'm gonna switch to a 17 pitch I'm sure that's the right one for my boat! Thanks for the advise!Just a quick note for GPS on phones. Seatow has an app for the iPhone that is free. It has GPS and Compass as well as weather and tide info. Not sure if they have it for the other smart phones. It is handy for GPS speeds if your boat doesn't have one. Also I have a 90TLRA 2 stroke Yamaha, I played with the pitch on the prop by going from a 17 to a 19 and lost RPM and performance. I am no expert by no means, but when I went back to the 17 pitch I regained my WOT RPM and performance came back. My boat is a Duracraft 1860BSBay. If you can borrow a few props in the various pitches you can experiment with your boat and see what gives you the best all around performance. Oh - both props were aluminum