Prop choice

StrokeBail

Cadet
Joined
Aug 30, 2016
Messages
7
So I bought a new Tracker Grizzly 1648 MVX SC w/ 30hp Merc 4 stroke. No RPM or GPS speed yet (no tach) but it def. is not planing and motor seems to be lugging, not in the sweet spot after minutes of WOT. Loaded with 240 lbs of me and maybe 150 of cooler, anchor, tackle, tools etc. Running at around 5500 ft altitude. Stock prop on the motor (boat and motor were new, 2014, less than 50 hrs so far) is an 11 pitch. Local marine dealer is unsure if I need to go to a 12 or smaller. Hole shot is OK I guess, just feels like starting a car in 2nd gear; not like 2 strokers I have used in the past. Asking too much of this boat/motor combo or might a 9p prop help? (my ignorant guess). I know I need WOT RPM (motor WOT RPM is 5250-6250 per spec sheet) but getting info on a tach is tough. Got one answer here (Thanks Silvertip) so far. Bass Pro and Tracker Marine not helpful. Any thoughts?
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
You need a tach and accurate speed by a gps. An accurate speed will help.
Your power is down about 15% at 5500 ft.
See if the marina will let you try a 9" pitch.
Try eliminating some weight or move it around a little.
You probably have a battery and gas tank near the stern?
 

StrokeBail

Cadet
Joined
Aug 30, 2016
Messages
7
Yeah, 5 or 6 gal. on same side as steering wheel which makes the boat list a lot at lower speeds. Tracker should have placed it on port side to offset weight of driver. Battery and gas tank are right up against the transom. Will try to locate all weight up front or take it out altogether. Can use my handheld GPS for the accurate speed. This boat was a 2014 leftover that sat outside at Bass Pro shops for over a year..I have read on this forum about waterlogged boats. Any reason to be concerned in this case? I'm leaning toward the 9" pitch. Thats a big power drop due to altitude, and I think I'm running 10% ethanol. Given all the above is it unreasonable to expect this scow to plane off eventually (long running start)? And thanks for the reply, steelespike.
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Best high altitude boating is a combination of rejetting along less prop pitch, could just re prop as a starter, Order a Hardline Tach/Hour model : [FONT=&quot] [/FONT][FONT=&quot]HR-8061-2 install it per instructions, report max wot rpm achieved lightly loaded.

GPS speed is relative, WOT rpm it's everything..

Happy Boating
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