IMPORTANT 150 XR6 QUESTION ! !

[paul white2]

WOULD SUM1 PLEASE ANSWER THIS QUES, I KNOW A BUNCH OF Y'ALL KNOW THE ANSWER. I HAVE AN 18 FOOT NITRO NX882 WITH A 150 HP XR6 MOTOR ON IT. OK, WHEN IT RUNS WIDE OPEN IT RUNS 4400 RPM'S TRIMMED UP ALL IT WILL DO ! ! IT HAS THE PROP THAT CAME ON IT WHICH IS A TEMPEST 23 PITCH SS PROP. I HAVE BEEN TOLD THAT THE MOTOR SHUD TURN 5200-5800 RPM'S WIDE OPEN !! SO WHAT I NEED TO KNOW IS DO I NEED TO DROP TO A 21 PITCH PROP??? IS THE PROP MY PROBLEM ?? TRIMMED AND WFO IT RUNS LIKE 4400-4600 MAX. THAT'S A 1000 RPMS UNDER WHERE IT NEEDS TO BE. BUT SUM1 TOLD ME ONCE THE 23 TEMPEST IS THE PROP IT NEEDED ON IT. BUT I KNOW DROPPING THE PITCH INCREASES HOLE SHOT AND RPM'S TOO. SO, WHAT DO I NEED TO DO?? WFO TRIMMED IT RUNS 55 MPH BUT IS RUNNING 4400 RPM'S IS ALL !! DOES IT NEED SUMTN DIFFERENT OR WHAT ?? AND, IF I DID DROP PROPS I KNOW RAISING THE RPM'S WOULD ADD ATLEAST 4-6 MPH TOO RIGHT ?? PLUS IT IS KINDA SLOW COMING OUT OF THE HOLE, SO IM THINKING THE PROP NEEDS DROPPED TO MAYBE A 20 OR 21 PITCH.......WILL SUM1 PLEASE EXPLAIN THIS TO ME I KNOW ALL YOU GUYS ARE PROS......BUT I'M NOT !! THNXXX ALOT.......PAUL

 

[Marty Klein]

So, how many RPMs does it run on WOT and trimmed up?

 

[Brian Ingersoll]

First off, STOP YELLING



I had one of those and the 23 Tempest plus is the right prop.

You said 55mph @ 4400rpm's, I'm going to guess thats speedo not GPS.

What is the engine height?

What is 'kinda slow' on your holeshot?

Is that loaded or light?



When you get it right you should be running about 61mph @ 5600rpm.

 

[paul white2]

MARTY THNXX FOR YA HELP......WHAT DOES WOT MEAN ???

 

[paul white2]

velcro thnxx alot.......you say it's the right prop but you said it shud be 61 at 5600 rpm's.....well thats what i was thinking too. when i gun the throttle it takes app 5 secs to level out. but i knew it shud be running more than 4400 rpms, and it runs the same with 1 or 2 people in it, usually loaded lightly id saay, but i do have 4 batteries in back, but i never have full tank of gas usually 1/2 or less and it still seems slow. so, what pitch would you say i need? 19, 20???? you guys know but i dont........thnxxxx

 

[paul white2]

velcro.......it has the manual jackplate on it that i was told came on the boat. it's in the second hole in the plate. does this help ?? i also know nutin bout a jackplate. any help is appreciated, i need and want the max performance from the motor though and i know 4400 is not max.......and the gps and speedo differs no more than 1 mph at anytime. so what do you thnk i need to do??

 

[John W2]

The Mercury Prop page is a good place to start and get information on prop selection. As well as this sight of course.
http://www.mercurymarine.com/propellers/prop-selector/#

 

[Jim B]

When i had mine i could turn clsoe to 6000 rpm with the same prop.



Something isnt right, i would get it checked out by a good mechanic. It could be fuel system related( like the throttle linkage is not adjusted right) or ignition( like a cyl not getting spark) get it checked out and elimiate any motor issues before you start messing with the setup of the boat.

 

[Mebassn]

If your running 55 on gps and taching 4400 i'd look at the tach or a voltage regulator. I have a 99 NX882 with an XR6 (original owner) and have had several different failures of components which lead to an rpm oddity. Next time you go out tap the tach at WOT and see if it jumps up or down. If it doesn't change then swap the gray connectors for the tach lead and run again. If it changes to normal indications then you might have a voltage regulator going bad. You could also have a coil going bad or not working, which means your only running on 5 cylinders. Just some food for thought.

 

[Bob Bourget2]

The "basics" are in order:

-1] Compression test

-2] Ignition systems check

-3] Fuel delivery, and quality.

-4] Verify tach accuracy.

Without these "first-to-look-at" tests, we are all "guessing".

 

[Brian Ingersoll]

I would be looking at the tach before I went anywhere else. 55 at only 4400 rpm's with a 23 pitch prop isn't going to happen. I would guess there is some other problem to be found, but getting the tach working properly is going to be the first thing you need to do.

 

[Jim clear]

I have the same boat, its a 2005 nx882 with the 150 merc xr6. I have the "setback" plate also. It is in the 2nd hole as yours and has the 23 tempest plus. At wot I get about 64 to 65 mph on GPS.(5600 rpm) I have learned all my stuff from these guys in here. I believe this is what the set-up we have is capable of so maybe there is a issue with fuel or something.