Who to believe?

[Eye owa]

Lund 1775 Proguide with 90s with a Black Max 17p prop. I think the RPMs, 4800, are too low at wot. I asked dealer about a stainless Spitfire x7 replacement and he told me to stay with a 17p. I dont know but I would think that such a Spitfire would only serve to lower my RPMs? From postings from Jeepman and R-Rigs I have read here, it seems like a 15p would be more fitting. My boat is shorter/lighter than both so I don't know. At the price of those props, I cant afford to "experiment."
What should I believe?

TIA

[Ndstallmann]

Start with the mercury prop calculator. Also some dealer will let you try props. On a side note I would start with 15 pitch.

[Hot Runr Guy]

A couple of things to consider;

1) Is your tach accurate, using SmartCraft maybe?

2) Does your 90 have the "standard" gearcase, or the CT (Command Thrust) version? Big difference in gear ratios.

HRG

[REW]

Put on the 15 pitch prop and enjoy the performance.

[WallyWarrior]

You will get better rpm out of the 17 pitch stainless because it won’t flex as much, if you’re currently using aluminum. With that said, you will not gain what you need from where you are. I would go 15 for sure.

I run a 15p x7 on a yami 115 w same size Lund boat. It is perfect on my rig. I can hit rev limiter on about 1 in 10 tries.

Sent from my iPhone using Tapatalk

[Boondock]

Originally Posted by Eye owa

Lund 1775 Proguide with 90s with a Black Max 17p prop. I think the RPMs, 4800, are too low at wot. I asked dealer about a stainless Spitfire x7 replacement and he told me to stay with a 17p. I dont know but I would think that such a Spitfire would only serve to lower my RPMs? From postings from Jeepman and R-Rigs I have read here, it seems like a 15p would be more fitting. My boat is shorter/lighter than both so I don't know. At the price of those props, I cant afford to "experiment."
What should I believe?

TIA

4800 sounds real real low with a 17 black max near sea level on that boat.
What’s your speed? It isn’t adding up

[Tdobb]

I gotta think the 15P Spitfire X7 is going to be the right prop for you. I run a 98 Ranger 681VS (17'-10" with 80" beam) with a 115 ProXS Fourstroke. I am running a 17P X7 on there and I can just barely tap the limiter (6300) on occasion. The Pro Guide is a foot wider, 150 lbs heavier, and 25 hp less. You will not hit your optimal RPM range with a 17P X7 on the Pro Guide 1775.

Here is a link to the Merc performance test on a Crestliner 1850 Pro Tiller with the Spitfire 15P aluminum prop...

https://mercurymarine.widencollectiv...rformanceTests