Prop size for 2018 Mercury 115/ 4 stroke - EXPLT ? Looking for a little more speed....

[doctorwedge33]

Looking to get more top end speed out of motor , currently on boat a Black Max 13.25 x 17 prop on a 2019 Tracker 175 Combo Pro Guide / Mercury 115 hp 4 stroke EXPLT

 

[Starbanker]

The Mercury website does have a prop selector tool that you can use. You'll need to know the weight of your boat with it's load added. https://www.mercurymarine.com/us/en/propellers/mercury-propeller-selector
From what I see is that the prop has a much smaller pitch that it could take. What is the WOT rpm? As long as you stay within the engine's normal operating range you can get a bigger pitch prop. The best way to find the right prop is a dealership that will let you try out a prop on the water. A good way to select one would be a prop that will be at the mid-range of the normal operating range, for example if the engine has a normal O R of 4700-5200 rpm look for one that would make your wide open throttle rpm at about 4950 rpm. That would allow for a good top end and enough torque for your hole shot.

 

[Dan Wilson]

I´m running a 19 pitch on my Optimax 115 on a Pro Guide V175 and get about 5200rpm but only get 40mph. I was hoping for 43. I´m not sure what the red line is on my motor

I´d be curious as to what you are getting top end now. Btw, my hole shot is great. So no issues there, even with a full load on board.

 

[Dan Wilson]

The Mercury website does have a prop selector tool that you can use. You'll need to know the weight of your boat with it's load added. https://www.mercurymarine.com/us/en/propellers/mercury-propeller-selector
From what I see is that the prop has a much smaller pitch that it could take. What is the WOT rpm? As long as you stay within the engine's normal operating range you can get a bigger pitch prop. The best way to find the right prop is a dealership that will let you try out a prop on the water. A good way to select one would be a prop that will be at the mid-range of the normal operating range, for example if the engine has a normal O R of 4700-5200 rpm look for one that would make your wide open throttle rpm at about 4950 rpm. That would allow for a good top end and enough torque for your hole shot.

That prop selector came up with the Vengeance 13¨ diameter 18 pitch for me, for top speed and overall performance. I wonder how many mph it would get me? 2? 3?

 

[doctorwedge33]

That prop selector came up with the Vengeance 13¨ diameter 18 pitch for me, for top speed and overall performance. I wonder how many mph it would get me? 2? 3?

Not sure how to reply , we are still under ice / snow so it will be a little while before boat gets out on the water .
I have read everybody is all keen on the Mercury X7 Spitfire more mph , hole shot and overall performance. Was wondering what exact prop pitch and diameter it is

 

[doctorwedge33]

Not sure how to reply , we are still under ice / snow so it will be a little while before boat gets out on the water .
I have read everybody is all keen on the Mercury X7 Spitfire more mph , hole shot and overall performance. Was wondering what exact prop pitch and diameter it is

Also it's a 4 blade prop

 

[Starbanker]

I´m running a 19 pitch on my Optimax 115 on a Pro Guide V175 and get about 5200rpm but only get 40mph. I was hoping for 43. I´m not sure what the red line is on my motor

I´d be curious as to what you are getting top end now. Btw, my hole shot is great. So no issues there, even with a full load on board.

Your operating range is 5200-5750, you are running at the low end which means your 19 inch is as high a pitch you can use.

 

[Starbanker]

Not sure how to reply , we are still under ice / snow so it will be a little while before boat gets out on the water .
I have read everybody is all keen on the Mercury X7 Spitfire more mph , hole shot and overall performance. Was wondering what exact prop pitch and diameter it is

The size of your prop should be engraved on it.

 

[Starbanker]

Also it's a 4 blade prop

Four blade props generally recommended for boats that are bow heavy and heavier overall at a cost of speed. More bite, more drag.

 

[doctorwedge33]

So finally today got boat out on the water, top speed 38 mph gps with full tank and 2 people / max rpms trimmed out 5750 .
Any suggestions to get more speed or is that it ?

 

[byron cooley]

What boat do you have

 

[byron cooley]

For me Laser ll was best, vengeance sucked

 

[doctorwedge33]

What boat do you have

2019 tracker pro guide v175 with a 115 four stroke

 

[byron cooley]

2019 tracker pro guide v175 with a 115 four stroke

You should have more speed than 38gps.
Sounds like way too much prop slip.
My Nitro 640LX has a tweaked 75hp optimax. Has no problem spinning a 22pitch laser II TO 5700 RPM 50MPH GPS with good holeshot.
I know my hull is different but you are loosing speed somewhere.

 

[doctorwedge33]

Does it make a huge difference how the motor is mounted on the rear of the boat ? There are holes that determine the height of the motor which is bolted to the motor mount. Mine is the very first hole where others are on the second height adjustment. Wondering for speed overall speed of the boat

 

[Dan Wilson]

Not sure how to reply , we are still under ice / snow so it will be a little while before boat gets out on the water .
I have read everybody is all keen on the Mercury X7 Spitfire more mph , hole shot and overall performance. Was wondering what exact prop pitch and diameter it is

Hi, I've been away for awhile. I just went from a Mercury Quicksilver Black Diamond 3 blade 13x19 pitch to a Rubex 4 blade (aluminum) 13x15 pitch. A guy at a local prop shop recommended it to me and said it should get me to around 5700 or 5750rpm and cure the cavitation, give me more trim range (raising the bow) and possibly, but not certainly, give me more top speed. I was at 39mph.

The cavitation and trim range are what is most important to me, but I would love to see 42 or 43mph. If not, I'm good, as long as the bow can come up more and the cavitation in turns is gone. He said having 2 blades in the water vs 1 will take care of both of those issues. He also said the hole shot will be much stronger, although that wasn't a problem before, being a 2 stroke. He said he's not sure that I'll see any gain in top end. But it is possible. He has about 40 years of experience propping boats, and has a sterling rep. Friends recommended him. Plus, the Rubex was a heck of a lot cheaper than a stainless prop.

Have you heard of anyone running the X7 Spitfire on the Pro Guide 175 with a 115?

If this thing works out, I'll sell the old one. It looks brand new. Of course, it should. It has less than 30 hours on it.

 

[Dan Wilson]

Here are some pics....

Old...3 blade and new 4 blade...

 

[Dan Wilson]

 

[doctorwedge33]

Here are some pics....

Old...3 blade and new 4 blade...

There are others in different forums running 4 blade spitfire props praising it's powers. Some say 42-43 mph with 3 people on board . I am personally going crazy with all these prop suggestions

 

[Scott Tschida]

Not sure how to reply , we are still under ice / snow so it will be a little while before boat gets out on the water .
I have read everybody is all keen on the Mercury X7 Spitfire more mph , hole shot and overall performance. Was wondering what exact prop pitch and diameter it is

I ran the 19 pitch 4 blade spit fire on my 2020 115 pro and loved hole shot and top speed of 52 mph. Was on 16 ft Ranger. Love that prop!