boat prop

[alexanderapearce]

i have a 90 bass tracker 1800TF with a evinrude xp 150 with a 14.25x24 and need to know what would be a good prop for this boat the hole shot and top end is just not where i think it should be it runs around 52 to 54 at 5500 rpms and i just had the power head rebuilt so any help would be great. emoBang

 

[yellburt]

<font face="courier new,courier" size="3">if wrenching2 dont respond to this post just pm him ,he will be able to tell you,but he may miss this post ,but i dont think he will ...he lives for these easy question.,..lolemoUSA </font>

 

[wrechin2]

Were do I start. There is alot of performance to be had from set up. Some props do make a difference but you set up needs to optimized for that prop. Hoepfully your prop is a raker. That is a very good prop. On my personal 17' boat... I was turning a 26 Big ear chopper on my 2.0L merc to 5900-6000 rpms and was GPS 55. Went to a 21P laser and went to 5500 RPMS and 52 MPH GPS. Just because the chopper lifted the boat more. But I had more slippage. Boat ran flat. Went from 6" setback to 8" and rpms stayed the same but MPH 61 GPS. Slippage went down. Went to 10" of seback and rpm stayed the same but speed went to 68 GPS. I gained 13 MPH by moving my engine back 4". Now keep in mind these numbers are wacked this is not the normal. They sound like BS but if it wasn't my boat and I hadn't seen it, I wouldn't have believed it. I have never seen another boat gain so much with 4" of set back. Bow flew high and I have several witness to this! The thing was The leverage lifted the bow and that is where my speed came from. Very similar to when you first take off and then you trim up. You feed the speed pick up cause the bow is raising.

MOST boats as a general rule of thumb need 1" of setback for every foot of boat. But hear me out....My boat for example was 17' so I needed 17" of setback. My boat had 5" built in and the engine has 2" (most do) so I already had 7" of my 17". I ended up with a 10" jack plate and the 7" of engine/boat set back and it was perfect. I tried a 12" and boat was uncontrollable.

So to answer you question....It may not be a prop issue but a set up issue.

 

[alexanderapearce]

ok i had a 110 with alu. prop with no jack plate and it ran 45gps and now i have a 150 stainles prop and 6" jake plate and it runs 52 to 54 i did see 57 the other day right after launch but then back to 53 steady.The prop is a raker but it don't look like my last raker it really dont have no cup in it,it almost looks like a prop for a runabout or a pontoon, i fell like i'm running in circles trying to figure this out(lol)so all the help will be so greatful

 

[wrechin2]

BEFORE WE BEGIN WATCH THE WATER PRESSURE!!!!!

A raker is a raker, some may have had more cup added to them. The are a pretty good surface piercing prop. The best way to "dial" in the jack plate is start at the bottom. Raise the engine up 1/4" increments and note rpm's and speed. Keep raising , while watching water pressure, untill the rpms and speed peak. Once the rpm's INCREASE and the speed DECREASES then you are close to the "sweet spot" Then lower it down 1/8" write down your results. Lower another 1/8" and take note which was faster. Then lower 1/8" again and put where was the fastest.

How is the bow raising??? Porposing alot?

 

[alexanderapearce]

no it has good lift and it rides real good, i was thinking about going to a four blade but not sure on what it will do

 

[alexanderapearce]

oh and on the water pressure i have a low water pick up on the foot so i'm good on that

 

[wrechin2]

SKY is the limit. I have a modified 26 big ear chopper for omc. They like to run high and are more efficient high. The LWP ususally slow the boat down about 4MPH due to the additonal drag of more lower unless you can raise it up. The raker is a pretty good canidate for running kinda high. You may just start where it is raising it up 1/4" and see if it picks up or looses speed. If it looses start going down in 1/4" increments.

 

[wrechin2]

Where you located????

 

[alexanderapearce]

dalton ga

 

[alexanderapearce]

what rpm should this 150 be turning

 

[brushhog]

HERES ONE FOR YA,I GOT 21 FT STRATOS,225 OPT, 6"HYD PLATE,TEMP PLUS PROP,THE BEST {GPS} I EVER COULD GET IT TO RUN WAS 74MPH ,TOOK IT TO A DEALER IN NASHVILLE TO GET IT DAILED IN,WITH A FACTORY TEST PILOT THE BOAT RAN 82 MPH!!WITH ONLY MINOR ADJUSTMENTS,I STILL CANT GET IT TO RUN OVER 74MPH???GO FIGURE

 

[yellburt]

<font face="courier new,courier" size="3">hit the gas an the trim switch an dont stop till you get it to run like the other guy.if that dont work take that black thing off the back an go get you an evinrude..then you will be happy.emoUSA .</font>

 

[alexanderapearce]

i have a evinrude 150 xp on it

 

[alexanderapearce]

and i aint happy if it was black i would run faster

 

[brushhog]

I GUESS THE POINT I WAS TRYING TO MAKE MAYBE ITS THE DRIVER??I THOUGHT AFTER FISHING AND OWNING 5 DIFFERENT BOATS OVER THE LAST 12 YEARS I THOUGHT I WAS A PRETTY GOOD PILOT,THE NASHVILLE BOY IN MY BOAT SMOKED ME!! AS FAR THE COLOR OF THE MOTOR IVE HAD EM ALL JAP,OMC,,THIS 2008 MERC BY FAR HAS BEEN THE BEST .

 

[wrechin2]

Brushhog, You have to learn how to drive it. If the boat will do that with him then it will do it for you. You may not be able to get it up on the pad which is good for several MPH. </p>

</p>

The OMC 150 is a good engine but porting makes it fall short on power around 5700-5800 they start running out of breath.Good bottom. I am building a 150 GT (same as XP just different color). I am porting it to 200 specs ( pulls harder at higher rpm's) and doing alot of "velocity" increases. When I get finished I am going to post a little "class" on hot rodding the x-flow. many pictures and explanations of why I did what. All a engine is is a air pump using fuel to make pressures to rotate it. The mods just make it more efficient and thus making more power at a different RPM. The x-flow blocks are the same for the 150/175 with just carbs being the different. The 200 has different port timing but the EXACT same internals. Then you get into heads and carbs are difference. The GT/XP 1 3/8 carbs are bigger than a 200's. The GT/XP's are closer to 175HP. But are allowed -/+ 10% of rated horsepower so they can get away with rating them 150's. Just like merc XR2, XR4, and XR6 engines are on the high sige of 10%. </p>

 

[alexanderapearce]

well the guy i got mine from told me that mine was a 200 with a 150 hood i just thought he was crazy and trying to get me to buy it, i really need to know what rpm range i need to be in and what speed range i am looking for i'm still pretty new to all this bass boat stuff but i work as a mechanic on big trucks and after have'ing to keep taking it back to the guy how was working on it i started doing it myself

 

[wrechin2]

Look on the top of the port head (left when viewing from the rear of the engine. There is a plug with a number. It tells you ALL you need to know about the engine, Johnson/ Evinrude, horspower, lenth shaft, year, ect. The number below it on the 2nd line is the serial. On the side of the trim bracket it will have a sticker with a model and serial. If the serial matches the one on the welch plug and the sticker it is the original powerhead. He may have been talking about it being a 175 with a 150 cowl and that is somewhat true. Not a 200. Pulling a head off and looking at the ports and measuring them would tell the story similar to the one I am doing.

 

[wrechin2]

I went with the tightest radius which is 3/8 ( the factory XP used 1/2 radius) and will have tapered edge to help the ring back into the piston. This keep it from hanging a ring. Even stock ports would hang a ring. SO this is done to all on a rebuilds. Hope these pics help.