150 Mercury Prop

[GraAlaMat77]

I have a 1989 Mercury xr4 blackmax. My 18 foot boat has a WOT RPM of between 5400 and 5600. Top speed is around 58. (with the motor trimmed up). Witout the motor being trimmed the speed is around 48. My current prop is a three blade, stainless steel, Rapture prop, I do not know the model number. It has a diameter of 14". The boat is a fiberglass bassboat. I am wondering what prop would be the best to put on the boat to acheive the most total performance (top end speed, hole shot, everything). Thank you.

 

[studlymandingo]

Re: 150 Mercury Prop

If you are at 56K at WOT then you have a good prop range for your rig.

 

[GraAlaMat77]

Re: 150 Mercury Prop

What about changing to a prop that has 4 blades instead of 3? Will that help in any way at all?

 

[walleyehed]

Re: 150 Mercury Prop

4-blade props are only useful if a jackplate is used, and generally, a 4-bld is being used for a specific reason.<br />If we're running a bassboat, we need to look into the Apollo, Stilleto, Turbo, Tempest, Laser type props...The Rapture is a great all-around prop, but not the highest performance available.

 

[tysdad2010]

Re: 150 Mercury Prop

I have a 1989 Mercury xr4 blackmax. My 18 foot boat has a WOT RPM of between 5400 and 5600. Top speed is around 58. (with the motor trimmed up). Witout the motor being trimmed the speed is around 48. My current prop is a three blade, stainless steel, Rapture prop, I do not know the model number. It has a diameter of 14". The boat is a fiberglass bassboat. I am wondering what prop would be the best to put on the boat to acheive the most total performance (top end speed, hole shot, everything). Thank you.

What is the pitch on the prop?

 

[jestor68]

Re: 150 Mercury Prop

Your 150 is right in line with other 150's on like size boats. I haven't seen a single test of one breaking 60 on an 18 foot (bass) boat.

If you want to break 60, get a 175 (63.4mph). Most were running Tempest props.

 

[tysdad2010]

Re: 150 Mercury Prop

Your 150 is right in line with other 150's on like size boats. I haven't seen a single test of one breaking 60 on an 18 foot (bass) boat.

If you want to break 60, get a 175 (63.4mph). Most were running Tempest props.

Hell I wanna break 50 before I can break 60 lol

 

[cajunmerc]

Re: 150 Mercury Prop

First of all an xr4 is a 175, hp @ the prop, 2.4 liter carb, the only thing holding her back is the can,awesome motors, the best thing for you on a heavy bassboat will be a merc trophy plus, unfortunately a 23 p is a tad big for the xr4 and the 21 too small, i use mark croxton for all my prop work and the ideal prop for that motor on your boat would be a 23 cupped/repitched to a 22., i have 3 of those xr4,s, and on an 89 cajun 18.5 bboat, i get 64mph at 5800rpm,w/8" setback and raised 3" below pad with a bobs cone on a 2:1 ratio gearcase , with drilled mid, i get 6200rpm out of a 23 tempest+ but hole shot is slower. The small case 1.78 factory l/u limits what diameter prop you can spin with that motor. If you can find a 2:1 135 case then get a 23 trophy, if stock then a 21 trophy will get her goin quick, but w/out a little prop work, you won't get her full potential. that motor will spin 6000 rpm all day long with oil injection delete and 50:1 premix.