Questions for the Prop Experts

A 250 should be turning a 21 pitch prop at way higher rpm’s than that. You should be running a 26 or 27 pitch. If all your getting is 5800 out of a 250 with a 21 pitch prop you have motor issues.

quote:

---

A 250 should be turning a 21 pitch prop at way higher rpm’s than that. You should be running a 26 or 27 pitch. If all your getting is 5800 out of a 250 with a 21 pitch prop you have motor issues.

---

All depends on load, hull type, motor height on transom etc. A few things will factor into pitch vs horsepower. You don't say what type of 250 4 or 2 stroke but there is a range you want to be in. Some say higher end of the range which I shoot for and some have a theory with less motor wear if below the max threshold of the range.

Is the hull bottom clean? Is the cavitation plate even with keel of the boat or maybe slightly above it if it's a fast hull? Are you trimmed up on plane when taking the RPM count at Wide open throttle? Is your prop in perfect shape?

You guys are right. I immediately saw 250 and never thought about hull type etc. I’m used to only high performance bass boats which is all I’m really familiar with. In that scenario a 21 pitch prop is entirely to small for a 250. Would have an unbelievable hole shot but shite for top end.

quote:

---

Depends on the hull, what kinda boat and how long?

---

24' Blue Wave Pure Bay.

F250, 4 stroke.

quote:

---

Is the hull bottom clean? Yes

Is the cavitation plate even with keel of the boat or maybe slightly above it if it's a fast hull? I have a jack plate I can raise.

Are you trimmed up on plane when taking the RPM count at Wide open throttle? I believe so, I can check that again.

Is your prop in perfect shape? It is in very good shape, no dings or dents.

---

I had my slightly dinged prop worked and it made a difference with grip at higher speeds, 55mph+.

I prefer to run a little hotter, 6000 or the top end of the recommended WOT range. My Suzuki has always run better pitched like that.

there are prop calculators on line that you can plug in your hull and motor and they’ll tell you proper pitch. Blue wave is certainly going to be one of the choices

How high is the motor mounted? Can you see the anti-cavitation plate above the surface of the water while running on plane? If your motor height is good then you're probably in need of a 19P prop. Someone said above that they liked Tempest Plus. I run those on my boat and they are fantastic for my hull. Eco Enertia is also a solid prop for heavy boats. You'll probably need a 17P in the Eco though. They don't hardly slip at all.

Prop Slip calculator

Anti-cavitation plate should be above the spray.

quote:

---

Do you have a 4.2L or 3.3L?

---

3.3L

Same boat and motor. M20 prop, Dinged four blade.

I get a little better than that @ 5500. Probably 43 - 45 depending on wind and current.

quote:

---

Same boat and motor. M20 prop, Dinged four blade.

I get a little better than that @ 5500. Probably 43 - 45 depending on wind and current.

---

What is an M20 prop? I couldn't find it with Google.