Need advice for a replacement prop...

[RockNemo]

I have an older 18'6 Cajun bass boat that I repowered last year with a Mercury 150 Pro XS, it replaced a black Max XR4 that had a small hub lower unit with a 26p High Five prop. This is a real heavy boat compared to todays screamers but with that old set-up it would run with full load at around 57-58 mph at 5500 rpm's. Now with the new motor and same prop it seams that the motor tachs out a lot quicker without reaching to same top end, and the boat doesnt seem to be riding as high out of the water. It runs around 50 mph when at 5600 rpm's. It seems to me that it needs a higher pitch prop but I have no idea what would be best. Any help from the more knowedgable people out there would be greatly appreciated. Thanks, Rick N

[David]

Interesting motor swap, at least to me. I daydream about switching to a green 150 from my XR4. Does the Pro XS accelerate a lot harder?

How fast did the XR4 go with the 26 high 5 at what rpm? Did the XR4 have the small gearcase or the large gearcase? You've probably got 1.87 gears and a 4.5" case now. The XR4s came with a 4.25" 1.78 gearcase.

I see a lot of Tempest and Trophys on bass boats.

[200VEGAS]

i would think maybe like a 24 trophy. do you have a jackplate, and does it have a torque master lower with low water pickups. also, a small hub laser about 24 maybe. with a heavy boat, i would think a lot of setback would work well.

[MDevrow]

Had a cajun espre 20' with 200 johnson gt, they are very good rough water boats but as you said they are heavy. Had to keep my prop low,below the bottom of the boat to get any bow lift and this took time but when it finally got on top would run 70. Prop was a 25 raker they have good lift, a comparable prop standard through hub should work --agree on a 24 tempest or a good lift prop, had to get mine up on top to get any topend.

[200VEGAS]

a raker wont fit a merc unless maybe a torque flo hub. the raker 1. hub is too long, good prop though. i bet a 22-24 chopper would be nice, if looking for over hub.

[RockNemo]

To all the questions asked: yes it does have a 6" manual jackplate, the lower unit is the stock one that comes on the Merc Pro XS and it does not have a low water pick up. 200Vegas, you mention a small hub prop Laser, is it better to have a small hub prop on a large hub lower? I didn't even know that my origanal props off my small hub XR4 would work, but the dealer put some kind of ring in them and that is what I'm using, I also didn't mention that I have a 24p 4 blade Hi Tech prop that I've tried with about the same results. Also MDevrow, you also mention about keeping the motor low, will that get my boat more on top, I've noticed with this new motor that the boats seems to be riding alot lower when on plane. And it seems to me that the way it performs its under propped, how would going from a 26p to a 24p help that out? Thanks for all the inputs.

[njj502]

Is the propshaft height the same? I'd try a Trophy, I just picked up a Fury and it's wicked!

[200VEGAS]

the small hub lets the prop ventilate on hole shot. i know trophys work good with small hub, and i think a laser would, but i dont know for sure. if it does, you wont have to drag that 4th blade with you and should run faster in my mind. as soon as i get my boat out, i willknow about the laser's cause i bought a 26 laser, and a 22 laser with a merc racing lab job on it. ill let you know how they work. the 22 might be just right for you. its going to be short for me, but i am going to try before selling it both are the small hub

[RockNemo]

OK great, let me know how they run. What type of boat and motor are you using them on. And another question, I see everyone here mentioning about their prop height, how is this measured?

[vnemous]

I think most of us measure prop height by putting a level on the bottom of the boat by the stern and leveling that first. Than trim the motor up or down and with a level on cav plate make that level. Than measure from the bottom of boat to ground and the center of prop shaft to ground and subtract and thats your height. Of course the ground should be flat too.

[MDevrow]

Good luck with testing, been boatin since i was 12 always loved trying new props. The cajun I had was so heavy I had to go low -center of prop shaft to the bottom of your boat-- = engine height-- not sure if yours has a small pad or not I had to have all my prop below the boat to get any lift. Anything over a small roster tail I would lose top end, You will kill your low end to get every last topend MPH.Know props are high$ look for a prop shop that will work with you Nothing wrong with a used wheel, find one you like keep it balanced and in good shape. 3 blade large hub merc. prop. 26pitch seems to much on a cajun, on a lighter boat 26 is still a lot of wheel for 150hp.Go test and have fun.

[200VEGAS]

i am running a 20 hydrostream vegas xt with a 200 2.4. i had a 2.4 for a couple years and lost a rod bearing, so i threw my sons 1982 150 (135 hp) on there for a while. with that small motor, i used mainly a 24 trophy. i tried a 24 chopper, and it felt good and turned about 6000 at like 60. a 24 trophy was a little slower out of the hole but ran about 6100 at 61.5 mph. just a little faster. i was running my 12 jackplate stock lower and i think i was like 2.5 down running merc scoops attached to the stock 2.1 lower to maintain w/p. me and him in the boat. the one day we were doing a lot of testing, my buddy had his boat there, and it is a 17 or 18' tidecraft. it has a 2.0 150 hp ,l no jackplate and pretty low in the water.he was down in the 57 mph range, and as i remember the chopper worked better on his boat. he preferred it to the trophy. i think the chopper was a little faster as well. i almost couldn't get it back from him. i would try these two, if you get the chance. were do you live, you could always try mine. im in orlando. the chopper lets you think your in a performance boat if its pitched for the 6000-6500 range even if your not. awsome feeling launchs, lots of bow lift. i would try the 24's and if they don't do it, the 22. you probably will want a couple anyway. you definitely will see more performance when you get to the right prop. i think a 24 trophy will slip more than the 4blade you have now, and go faster and feel better. 22 chopper would probably work real well to, maybe turn 6200. whats your limiter set at?

[Capt.Insane-o]

Tempest Tempest Tempest.. they work killer on boats that need a ton of lift.

[rkmirage]

:iagree::iagree::iagree: 24 Tempest is best bet, I don't think you'll like a Chopper, not on a heavy boat.

[200VEGAS]

Do you think he can turn a tempest 24 with the large blades? Maybe a 22. I guess there would be one way to find out. I've actually never used one, so i cant say... Do they have large blades? At least with a 24 chopper, you can pull a little taller pitch cause of the o/h design. But choppers arent for everybody. More of a single purpose go fast prop i guess.

[rkmirage]

Do you think he can turn a tempest 24 with the large blades? Maybe a 22. I guess there would be one way to find out. I've actually never used one, so i cant say... Do they have large blades? At least with a 24 chopper, you can pull a little taller pitch cause of the o/h design. But choppers arent for everybody. More of a single purpose go fast prop i guess.I would think he could turn a 24, only way to know is to try.

[RockNemo]

Thanks for all the inputs. I really only want to hit what is recommended for WOT which is 5600 rpms, I'm sure it will do more before limiting out, but I'm really only looking for longevity, not max speed. What I dont understand is with this new 150 Pro XS, that it is much more responsive and powerful, and using the exact same props I had on my XR4, I'm going a whole lot slower and not riding as high on plane. Does going from a small hub lower unit that was on my Xr4 to this new one make that much difference? Also another thing, how would a 24p Trophy Plus or 24 Tempest be any different than my 26 High Five or 24 Hi-Tech props? I know a local gentleman that has a like new Trophy Plus (PN 48-825940 24p) that came off his Bravo 1 outdrive, will that work on my lower unit and should I even try it? Just seems they are about the same thing I have, thats what I dont understand. Rick N

[rkmirage]

Xr4 is a 1.78 gear ratio, you have a 1.87 on the new one, same rpm, it will be slower and ride deeper, go up in pitch. A Trophy would probably work well on your boat.

[RockNemo]

Ok, that makes sense on the gear ratio. But can you explain why using a Trophy would be any different than using my 26 High Five or 24 Hi-Tech-4.

[200VEGAS]

more efficient design of blade, less drag, less slip. thats the idea anyway. its all about that prop that has the right combination of the best blade style, rake, diameter, and pitch to let you run the most speed at the least rpm. (lowest slip percentage}. have you ever used the prop calculators, and what kind of speedo pickup was used on your testing. were you using gps? 50 is not what i would have thought that boat would run. have you ever ran the boat up on a scale? sorry if i'm rambling, i for some reason thought you were after rpm.

[resqu-u]

I have a friend with an 18' Stratos DC fully loaded to fish, 3 27's on board charger, etc.. so he's really heavy and running a 150 pro xs. He is using a 24 tempest, it runs good I think mid to high 50's. He says it could be a little faster out of the hole. Sorry Vegas he doesn't need a chopper, I'm not sure on the trophy, but the tempest sounds like a good fit. Look on BassBoatCentral, don't flame me guys LOL. Most of the boats on there are a little more like yours and the props you see will work better. They have a forum just for Cajun's so guys that know your boat can help you out. Stay on here for tons of good info and great people though as I'm not trying to throw any of the guys help so far. Good luck with the search!

[RockNemo]

200Vegas, I've been basing my numbers off GPS and I believe I have too much rpm as it comes out hard but seems to hit top rpm alot quicker than before with now only getting to 50mph compared to upper 50's. And resqu-u, thats real close to what my set-up is, a 18'6 DC loaded with 3 31's, onboard and a real heavy hull. With my old XR4 I hit upper 50's with these same exact props, thats what makes no sense to me. Some mention its the gear ratio difference, that seems logical. I will try to find a Tempest around here locally so I can try it out. How bout that 24 Trophy Plus, would it be worth trying or is that prop not what i need. Again you guys are all great in helping people like myself out, these props are expensive for me to just try buying to hope it works, I would like to get it narrowed down before I commit.

[200VEGAS]

try the trophy, and there is a 24 tempest for sale on the board now. you could resell if it doesn't work. i was just reading other peoples setups, and most run in the 50mph range with smaller 21p or so props. pull it up. i just put in the search engine {setting up 150 pro xs} merc testing on a 18' went 58 at 5600, and it was probably a lot lighter boat than yours. and it seams most like the tempest, and i think the merc site recommended it as well. course thats probably general recommendation for bass boat. i read its rpm 5250-5750, 413 lbs, 1.87 gears,6.5 mpg cruise at 3250. 60a charging system. i think the 24 trophy would act like a smaller pitch and might work well.

[RockNemo]

I want to thank all the people that helped me with my boat setup. I found a 23p Tempest Plus here locally that was in pretty rough shape, when I tried it out it got me a top end about 58 at 6000 rpm's. After talking with Mark, he said my tach must be off because I should have been hitting the limiter on my 150 Pro XS, after discussing some numbers I sent him the prop to get reworked. I got it back yesterday and all I can say is Holy $#!&, this boat never performed like this in the twenty years I've had it. The holeshot and lift is unbelievable, and my top end is now 62.8 on the GPS with my tach reading 6000rpm's, which I figure now is about 150 rpm's to high, as I did tickle the limiter as I kept it wound out. This will work out perfect as here in Florida its pretty cool right now, so when our warm weather returns it should drop it down into the perfect range. I'm running it at 4" below the pad with 18 PSI on the water gage. When it gets back to being hot here I may try to raise it up some, but right now I'm thrilled to what its doing. I want to again thank Mark, he does do amazing things with those props.

[MDevrow]

Rock good news on the Tempest, sounds like you've got a strong running 150.

[steve@scp]

with the torque that pro xs has a... TEMPEST fo sho!