Just when I thought I had it figured out (Fury3/4)

[J'Beaux]

2007 Triton 21X2
2007 250 ProXS
10" Bobs hyd jp

Ive been running a 25p 3 blade Fury too 5900 for an average of 63 mph after adding a Garmin Force on the bow. Prior to the Force I would run 66'ish.
Finally found a 25p 4 blade Fury hoping for more lift. I found one and got more lift better hole shot plus more speed 66.7 mph. The kick in the pants is I can only turn the Fury 4 @ 5000 rpm.
I know that is lugging the engine so I need to drop down in pitch possibly too a 23p Fury 4 according to the numbers. Should I expect my mph stay the same, drop or rise with a 23?

On a side note anyone want to trade a 23/24p Fury 4 for a 25p Fury 4?

[Bkp2609]

The fury 4 same pitch as the 3 blade should turn about the same rpms or maybe a little more. So @6000 instead of 5000 sounds right. And with a gain in speed it sounds like the tach is off. No way its faster being a 4 blade and 900 less rpms. Hope this helps

[J'Beaux]

Didnt think about the tach being off.... is there a DIY way to check it?

[Bkp2609]

Im for sure no mechanic but ive run a ton of props. Keep the 25/4 until you make sure its not the problem. The rule is if you can turn the fury3 , then the fury 4 same pitch is the one to run. And like you said its a little better since it lifts more. Sounds like you have the right prop. Maybe next time out the rpms will show different and be in spec. Dropping down in pitch will be slower mph

[Fishysam]

Often times there is a knob on the back of the tack, note its position, then adjust it they seem to have 5 spots. If no other rpm appears correct put it back in it's original position and it may be working better now. But I agree something is odd about your rpms

[redxdu]

This costs a little money ($200 or so I think?), but it will make you a much better DIY guy in the long run. Buy yourself a Merc Vessel View Mobile from European Marine and you will get the exact RPM from your CPU, along with a bunch of other good data and some neat features for doing top speed runs. Its not earth shattering but it's super easy to hook up and it turns your phone into a smart craft guage. I bought it for the exact same reason you need it. I was trying to figure out props on an older boat and I didn't trust my analog tach. Glad I did.

[J'Beaux]

Definitely some helpful comments guy's, Thanks.
Redxdu... I actually have a vessel view but I have never been able to get it to work. From what I'm being told it's something on the engine side that is not working properly...

[Jtreed99]

If he’s only getting 66 with a 25p fury4 he’s certainly lugging the engine. On my 07 21X2 with 07 proxs I run a 24p fury 4 and see 72 at 6050 rpm. I bet he’s not getting more than 5200-5300 rpm. I can’t explain his 3 blade numbers a fury in 25p turning 5900 should be mid to high 70s!

[redxdu]

Definitely some helpful comments guy's, Thanks.
Redxdu... I actually have a vessel view but I have never been able to get it to work. From what I'm being told it's something on the engine side that is not working properly...

Now that you mention it I did have one minor snag when I first hooked mine up too. Mine was on a 2005 optimax and I didn't have the yellow terminator plug that you need. Newer motors come with one already installed. The older ones must not of. If I remember right this is what I had to buy and then it worked great.

https://www.boats.net/product/mercur...IaAkOPEALw_wcB



Heres a good product manual for Vesselview. https://embed.widencdn.net/pdf/plus/...l.pdf?u=orhjei

[BuddyT]

You got problems, and I would suspect tach as mentioned. Mercury slip calculator is showing 21.05 percent slip, and that is figure with 25 instead of 26. A 3 blade Fury runs stiff compared to a Tempest. Most people would run slip numbers with 26 and that shows 24.06 percent. The 4 blade is showing 5.16 percent with is fantastic if it is true. Normal numbers should be in 8 to 11 range. Also Fury 4 will run a inch to 2 higher than a 3 blade fury. Tach numbers make no sense, something is off

[J'Beaux]

Again, great and helpful information. I'm going to check and see which terminator cap I have on my VV this weekend.
Found a 24p Fury 4 that I will be picking up tomorrow and see what it will do.
As a side note the 25 Fury 4 liked pretty much the same PTP as the 25 Fury 3 (Fury 4 bout 1/2" higher).
I have never really measured my PTP since I have a hyd plate which leads me to a stupid question..... How do you correctly measure the PTP on this boat since it has the step up in the hull? I assume you level off the bottom of the hull and not the steeped up part.
JTreed.... I may need to get some detailed info on your setup! Sounds like yours is dialed in.

[BuddyT]

Go to bass boat set up forum, they have a sticky on how to measure prop to pad. Helps to have a helper when leveling the pad, or you will crawling out from under the boat a bunch.

[Jtreed99]

JBeaux I got my best light loaded performance with a stock 25 tempest, ran 74.1 at 3 3/8” below pad in cooler weather. Holeshot suffered badly with full load in summer. I’m 3 5/8” with the 24 fury 4 and even in 90+ Degree weather, 3 200+lb guys and tackle, case of water, 52 gallons gas and 42 gallons water in wells I can hit 70 when I want and holeshot remains good. I don’t have poles or anything but have 4-31agm batteries and a 36v ultrex on the nose. I put a 4’ level on the center of back section of pad and level with trailer jack. I put torpedo level on cav plate and level with trim. Then I measure back on pad to garage floor and center of propshaft to garage floor and take the difference to get PTP. I got lucky and didn’t put a lot of time into setup with good results so I never touched again. Some guys spend loads of time on our hulls just to get to 68, some guys never touched it and are running slightly faster than me.

[wtailhunter57]

What is your prop to pad? If you are too high you get more slip thus higher rpms and less speed. Too low you will keep more boat in the water and turn less rpm.