Nitro 482 top speed issues

[francesco_dibene]

Hello everybody, this is my first post.

I recently bought a Nitro 482 (2007 model, single console, with very low hours on its Mercury Optimax 115). And I found out some general problems with the boat, especially the top speed (the boat leaning to the right is a known common problem it seems).

Running with low fuel and light tackle, I can't get past 38-39mph at 5500rpm. I trim all the way up until the engine stops (the gauge indicate 1/4 and that's odd...) but that's the maximum speed I reach. What can it be? I checked my engine in an official mercury dealer and it is perfect, I have a Laser II 21p prop and what I know from people who owned the same rig, it should go around 51-52mph.

Can it be the engine that is mounted too low (I don't have a jackplate, so test it takes time and money).

Thank you all for the help and sorry for my bad english.

[dan02gt]

Your prop is slipping like crazy. It could be that the prop is damaged, worn, or out of spec or that your motor is to high.

[francesco_dibene]

Your prop is slipping like crazy. It could be that the prop is damaged, worn, or out of spec or that your motor is to high.

thank you for these info. the prop is indeed a little damaged, tomorrow I will try to replace it with a 19p that is in good condition. The mechanic is talking about raise the engine and not lower it. I was thinking the same as you to be honest but he seems pretty sure...

[06 SB]

You'll be able to get this. It may take some time and experimenting.

A couple of questions for you...

As far as the trim goes, is it an analog or digital guage? Analogs are notorious for being off and can easily be adjusted so that at full trim it will be straight up. This is really no big deal.

In what hole is the engine mounted? (There should be 5 possible holes)

Have you tried a Trophy Plus prop?

Are you sure your tach is correct?

06

[francesco_dibene]

You'll be able to get this. It may take some time and experimenting.

A couple of questions for you...

As far as the trim goes, is it an analog or digital guage? Analogs are notorious for being off and can easily be adjusted so that at full trim it will be straight up. This is really no big deal.

In what hole is the engine mounted? (There should be 5 possible holes)

Have you tried a Trophy Plus prop?

Are you sure your tach is correct?

06

I really hope so!!!

About the questions: The gauge is analogic, so it can be indeed off. I'm not sure about what hole the engine is mounted in, I need to check this. About the prop: no, I did not tried it yet, this is my first bass boat and I'm still trying to figure out everything.

I will try a 19p steel prop tomorrow (the shop have one used) to better understand if the damages on the prop can really make this big of a impact (there is no cavitation, and the boat turn pretty well, even though the wheel pulls on the right pretty strongly).

The speed was checked with a GPS, and the tach is very precise after the double checking....

[TMG]

The wheel pulling to the right can be fixed by turning the torque tab to the right ONE notch at a time. One notch worked for me.
I also think the 19 is to small but for free why not give it a try. I bet youll have a good hole shot with it.
I have an 06 but have no idea how fast I can go. Im too busy fishing with it.
You will learn to drive without the falling to the right. a little bump to the left with the wheel and trimmed corectly and you wont even notice it after awhile, you just need some seat time. It is pretty weight sensitive so make sure your balanced on each side.
There are a few 482 owners on here that have spent some setup time and should eventually chime in.
Good luck and Welcome aboard

[francesco_dibene]

I wasn't able to test the new prop, because it was suited for a 150hp optimax. I've tested and made a video, it seems to me that the boat is very deep in the water, but the RPM seems pretty much right... I don't understand....

here's the pic... WOT.

brum2.jpg

[TMG]

Why would they have a 19 set up for a 150 ?
Are there any other dealers around to help you.
Someone will eventually help you here but it may take a while.
We don't get much traffic for 482 questions. You should maybe post this in the setups section.
Their going to need some more info like prop to pad measurements.

[hatcreek]

Francesco, welcome to BBC.

I've got the same rig as you... year, SC, outboard and prop. My engine will turn that 21p 5800 and run ~51mph with a normal load.

You're close on rpm's, but way off on speed. I hope it's just a result of the damage to your prop and that repairs will allow your boat to perform as it should. And I agree with Tim... a 19p prop is not enough unless you're using it to pull tubes or skiers.

I'm wondering which bracket hole your outboard is mounted in?

Mine is one away from all the way down (difficult to see unless you can zoom the photo)...



Also, I've never experienced the "leaning" issue that's been reported by some folks with this hull/engine combo.

Hope you're able to get everything squared away.

[francesco_dibene]

Francesco, welcome to BBC.

I've got the same rig as you... year, SC, outboard and prop. My engine will turn that 21p 5800 and run ~51mph with a normal load.

You're close on rpm's, but way off on speed. I hope it's just a result of the damage to your prop and that repairs will allow your boat to perform as it should. And I agree with Tim... a 19p prop is not enough unless you're using it to pull tubes or skiers.

I'm wondering which bracket hole your outboard is mounted in?

Mine is one away from all the way down (difficult to see unless you can zoom the photo)...



Also, I've never experienced the "leaning" issue that's been reported by some folks with this hull/engine combo.

Hope you're able to get everything squared away.

My outboard is mounted in the same bracket hole as yours. That is worrysome... the mechanic still insist to put it higher, but I think it may be the prop.... What about the weight? where do you keep the batteries? I have 2 in the front and 1 on the back (left side).

[CANNITRO482]

My outboard is mounted in the same bracket hole as yours. That is worrysome... the mechanic still insist to put it higher, but I think it may be the prop.... What about the weight? where do you keep the batteries? I have 2 in the front and 1 on the back (left side).

That might be your problem, I have a 150 on my 482 and even with that much power I have 1 battery in the front and 2 in the back. You are probably getting no bow lift

[francesco_dibene]

That might be your problem, I have a 150 on my 482 and even with that much power I have 1 battery in the front and 2 in the back. You are probably getting no bow lift

I will try moving them. I've read several forums that state that pur too much weight on the back on the 482 could be a problem

[TMG]

I will try moving them. I've read several forums that state that pur too much weight on the back on the 482 could be a problem

I would Send Hatcreek a pm asking where his batteries are before you go through the trouble.
only because its a bit of work you may as well ask before getting in to it.
I guess you could just pull one out and put it in the back without wireing it up and see what it did.
great now you guys have me thinking

cannitro482, did you start with a 115 and upgrade to the 150 ? I would love a 150 on mine !!

[06 SB]

When I had a 115 on my NX750 (similar hull), the motor was mounted in the top hole. I had it raised to put it in the middle hole (3rd from the top). It ran MUCH better and faster afterwards.

Do not change too much at once. Change one thing then go on to the next if you want improvement. For me, I would not change a thing until you get a good prop on the motor then see what it does. I have two group 27 batteries in up front and just the cranking battery in the back. Even with a 135, the bow lift was fine. If you need more, send whatever prop you settle on to Mark Croxton for some added bow lift.

06

[CANNITRO482]

I would Send Hatcreek a pm asking where his batteries are before you go through the trouble.
only because its a bit of work you may as well ask before getting in to it.
I guess you could just pull one out and put it in the back without wireing it up and see what it did.
great now you guys have me thinking

cannitro482, did you start with a 115 and upgrade to the 150 ? I would love a 150 on mine !!

I started with a 90 opti and that only lasted 1 year then I put a 150EFI, that was great but the pro xs is SOOOOO much better for gas and gets a little more speed with it too I also have my motor as high as it will go with NO jackplate

[TMG]

I started with a 90 opti and that only lasted 1 year then I put a 150EFI, that was great but the pro xs is SOOOOO much better for gas and gets a little more speed with it too I also have my motor as high as it will go with NO jackplate

Nice I only have the 115 but have a 6" hyd jackplate. maybe some day I'll dial it in. I have good intentions untill I get on the water and I cant put the rod down

[francesco_dibene]

I'm trying change the drive sleeve that could be damaged.... then I will try move the batteries on the back.

[06 SB]

The prop nut for a Laser II gets tightened to 55ft-lbs. You can damage the delrin sleeve by tightening it until the trailer tires lift off the ground...ask me how I know.

06

[hatcreek]

My outboard is mounted in the same bracket hole as yours. That is worrysome... the mechanic still insist to put it higher, but I think it may be the prop.... What about the weight? where do you keep the batteries? I have 2 in the front and 1 on the back (left side).

Sorry... I've been away from a PC for a few days.

I've got 2 group 27's up front and the cranking battery aft on the driver's side... No problems whatsoever with bow lift.

[francesco_dibene]

yesterday I had a full afternoon for testing some solutions.

I bought a new drive sleeve because the mechanic though it may be damaged, we mounted it and tried a test run, the result was:
- increased motor vibration at low speed
- a lot faster hole-shot (less than 2 seconds)
- same top speed and same RPM (5500)

Then we tried moving one on the front batteries on the back, the result was:
- same motor vibration at low speed
- same hole-shot as before the drive sleeve change (around 5-6 seconds)
- increased speed by 2mph (same top RPM, 5500)

We then tried to follow the mechanic idea and moved the engine up by 2 holes (now it's on the 4 hole from the top), we then put the boat back on the water and made a test run, the result was:
- lower maneuverability at low speed
- very very stiff steering wheel during the plane making the turns very difficult
- increased the top RPM to 6000+ (the alarm bipped 1 time)
- decreased top speed by 1mph
- decreased leaning of the boat when decreasing speed

The mechanic suggested to lower the engine by 1 hole (put it on the third). I'm still not convinced. What's your idea?

Right now the situation is pretty much unchanged, even if the new drive sleeve increased the performances by a little margin. still max speed around 39-40mph (with no gear, low fuel and 2 big guys)