Spitfire X7

[Deerchaser]

Interested in one of these for my boat listed below. Question is which pitch. Some may have read my other post about Trimming past my max RPM with a 17p. Im not happy with my current eco powertech prop. Horrible steering torque, feels/sounds like too much slippage going on. Im leaning towards staying with 17p in the X7. Are there any RT178/75 4s owners running this prop?

[Skeeterbait]

Just a guess but I think you are correct to stay with the 17p. The 4 blade X7 is a little smaller diameter but it has excellent bite. You are probably getting prop slip on your current prop contributing to the excess RPM. I am running a 19p X7 on my 115 RT188 and just making 6000 RPM in hot weather, a little more in cold weather. I am doubtful a 75 can turn a 19p to full RPM.

[Deerchaser]

Merc prop selector suggests 19p even if i enter the the motors max rpm. I just dont see a 19 working

[Lape0019]

On the prop selector, what does is calculate the RPMs are with the 19?

I know when I used it to try and figure out a new prop for my boat, it always showed RPMs lower than max.

[Deerchaser]

If i enter 5500, it says 19. If i enter my true rpm of 5700, of course its 19 again. As stated above, I think my over revs are due to slippage. Mph doesn't increase with rpm. The powertech i have is a eld3, equivalent to apollo. 13.38 dia. Motor in second hole.

[Deerchaser]

http://www.ptpropeller.com/content-p...r_mercury.html

[gatorglenn]

The prop I would use is PTRAF 17p. You have the wrong type of prop now. On prop selector the rpms give most of the time is where the power band is at it best for that particular motor. As an RPM range of say a motor 5500 to 5800. Inside that small band there is a efficiency spot where it gets the best RPMs rating and also the best efficiency for fuel economy. Like my motor is rated 5500 to 6000. But it's most officiant rpm is at 5750.

[Deerchaser]

This prop was dealer installed, prob too late to do anything now.

[fishon396]

Glenn, What is a PTRAF 17p. I have the same set up and would like to try a new prop also other than the Black Max 17p

[Deerchaser]

Powertech RAF series prop 17" pitch

[fishon396]

Thanks Deerchaser for the information.

[GeauxTide]

I bought an X7 21" for my Stinger, based on the Merc Prop Selector and that I was already turning a 22" Laser 56-57k Big Mistake. Wouldn't turn 5k. I'd talk to your local prop shop or dealer. My money says a 17 X7 will be too tall.

[Deerchaser]

I bought an X7 21" for my Stinger, based on the Merc Prop Selector and that I was already turning a 22" Laser 56-57k Big Mistake. Wouldn't turn 5k. I'd talk to your local prop shop or dealer. My money says a 17 X7 will be too tall.

Thanks!

[Sharp1C]

I have a 2014 crestliner vt17 just about same boat. I am running the X7 in 17pitch on a merc 75 fourstroke. My motor is the older style though not sure how much different they are.

[Deerchaser]

Dealer stepped up, x7 on the way.

[LAG ISSUEZ]

Dealer stepped up, x7 on the way.

That's awesome! Post results

[Deerchaser]

I give them the powertech ELD back with $100 and receive a new spitfire x7 13x17. I pray it isnt to tall. Powertech also told me the eld wouldnt work with an RT. No lift, no cup.

[gatorglenn]

I give them the powertech ELD back with $100 and receive a new spitfire x7 13x17. I pray it isnt to tall. Powertech also told me the eld wouldnt work with an RT. No lift, no cup.

Correct on the ELD.

[dwardmba]

Looking forward to seeing how it does. Bet it does great.

[billycal]

I give them the powertech ELD back with $100 and receive a new spitfire x7 13x17. I pray it isnt to tall. Powertech also told me the eld wouldnt work with an RT. No lift, no cup.

I had the x7 on my tracker 175 txw and it was great. On plane fast and 42 mph top end all with a 12' talon on the boat.