Prop help please.

[Texasmark]

Where did you get the 21? New or used? Seems to me something is squirrely, like maybe you have an intermittent hub slipping problem. Take it off, if it's not off already and scribe a line from the center of the hub....bronze splined area, out to the outer casting, including marking the outer casting material. Put it back on and take it out and romp on it a few times. Take it off and check your line. If it moved, get the 21 repaired (new hub) and put it back on. That should be your sweet spot on prop pitch.

 

[WesNewell]

I have no idea why you would want anything less than a 23p prop. Here's what the mercury prop selector recommends.
[h=3]Your setup[/h]

• Boat type: Bass
• Usage: Overall good performance/0 ft
• Engine Manufacturer:
  Evinrude
• Engine Type: Outboard
• Engine Year: 2001
• Number of Engines: One
• Engine Family: V6 DFI 2-Stroke
• Engine: 150 Ficht
• Drive / Gear Case: Evinrude 135-250 hp 2-S 1.86 Ratio

[h=3]Details[/h]

• Calculated Pitch: 27.72
• Calculated Weight with engine(s): 2,219.00 lbs
• Calculated Engine RPM: 5,000
• Calculated Boat Speed: 63.71 mph

 

[d75bender]

Ok, gonna reply to the last few replies...derekpittx….the 19p fits on my rude just fine. I just don't like the feel of it on my boat.

Texasmark...the prop I'm currently using is a used prop that I bought off Amazon but looked pretty new. The hub is the same hub that I used in my 23p, 19p and my 21p so it's not a hub issue. For the Turning Point props they all used the same model of hub and I used the same hub in each prop. I was thinking it was something with the used prop but not sure.

WesNewell...I used Turning Points Prop Wizard to select my prop. It recommended I use a 19p. But like I just typed there was still a lot of throttle left when I reached my engines RPM range of 52-5500rpms. So I went up to a 23p and it felt perfect but someone suggested that I should be running a 21p so I went with that which is what I have now.

I have a Renegade 27p prop that came with the boat and it slips, doesn't push the boat correctly if I get more than 1 person in the boat. It's not a spun hub, I can get on a plane with 2 people and all that but the boat doesn't feel right. It ventilates which is the slipping I'm feeling.

The 23p was the sweet spot for my boat so far. I'm looking to go back to that. I guess I'll try Mercury's prop selector and enter in my boats information and see what it says.

But so far I had:
27p prop that was horrible. Would ventilate constantly.
19p prop that felt great but to much throttle left at my engines rated rpm range. Couldn't go WOT or the rpms would get to high.
23p prop that felt great, no problems at all. 1 person in boat at 59mph. Never had 2 people in the boat with it.
21p prop that doesn't feel right for my boat. 56mph 1 person it boat.

Took it out again yesterday and it felt OK. Not as good as my 23p so I'm still looking to go back to the 23p.

Thanks for all the input.

 

[d75bender]

@WesNewell...just tried to use Mercurys prop selector and my engine is a 1997 Evinrude Intruder FICHT. The selector only goes down to a 2001. I used the 2001 150hp FICHT though and the results were all 23p props with a top speed of 59.34mp which is exactly what I had with my 23p prop previously.

 

[Texasmark]

Go-fast.com: https://www.go-fast.com/Prop_Slip_Calculator.htm

Plug in your LU ratio, like for 2:1 just insert a 2. fill in the rest of the first blocks and click on solve for max speed, leaving the last 2 blanks initially. Max speed is independent of any slip...like a screw in wood. Then put in your actual speed in the last block solving for prop slip.

Slip depends on prop and hull to water interface. at WOT on a reasonably fast hull it will be in the single to low double digit range. If your slip appears to be high, like 20% for a reasonably fast hull, then something is wrong with your inputs, tach or speedometer are giving you bogus info.

When playing with pitch, just leave slip where you were with it and play with pitch. Like you were running say 5k rpms with a 24 pitch, clear the pitch and rpm windows and insert your new pitch number leaving everything else alone. The answer will be your rpm with that pitch causing the same boat performance....just an example of using the chart for giving you an idea as to what changes will affect what.

 

[WesNewell]

@WesNewell...just tried to use Mercurys prop selector and my engine is a 1997 Evinrude Intruder FICHT. The selector only goes down to a 2001. I used the 2001 150hp FICHT though and the results were all 23p props with a top speed of 59.34mp which is exactly what I had with my 23p prop previously.

The reasons it may have come up with a 23p instead of the 27p I got when I ran it are many, including, boat weight, which I entered as 1200#, people and gear, which iirc I entered as 500#, and altitude, which I left sea level (0 ft.), and fuel, which I entered a s20 gal iirc. The most important thing is making sure the engine is mounted at the proper height. At the wrong height, performance can vary by 20%.
Assuming you are getting 59mph @5200rpm with the 23p prop, that's just a 3% slip, which is excellent. Even if you are at 5500rpm for that speed, it's still pretty good at 8% slip.

 

[d75bender]

I went back and re-entered other stats and it came up with different pitches for the prop so you're right about that. I don't have a jack plate on my boat and the engine was rebuilt by the previous owner, I can tell the motor's height has been changed previously. As to when it was changed, your guess is as good as mine. I can tell by looking at all the different mounting holes for the motor and you can obviously see where the bolts were at one point in time.

But with that 23p I was getting 59mph @5200rpm and it felt like the perfect fit for my boat. I already ordered a brand new 23p, the same prop I had previously so I'll stay with that. I'll report back once I take it out with the new 23p prop. It won't be here for a little over a week so its gonna be a second.

Thanks for all the help and suggestions.

 

[d75bender]

Had the boat out today with the 23p prop and it felt sooooo much better than the 21p. Felt smooth, no ventilation, no noticeable slipping at all. I had 2 people full gear and the stats stayed darn near the exact same as when I had it out by myself if not a tad better at points. 58mph for the most part at 5300rpms. Even touched 60mph at 5500rpm's when trimmed just right in calmer water. It was a little rough out on the lake today so I'm sure by myself I'll be hitting 60mph with it. Not to shabby for a 150hp motor and a Turning Point prop which was way less expensive than a lot of the other SS props I was looking at. Was on my brothers boat last week with a 250hp on it and it was only hitting 69mph. I've been told the 374V isn't Rangers fastest hull so I'm sticking with this prop. Tired of changing it back and forth lol. Thanks for all the help, much appreciated.

 

[roundcubesix]

How do you change the prop on a Mercury outboard? shareit vidmate vidmate app