Nitro 901 CDX sluggish hole shot

[Borkman]

    Greetings, I'm new here and a new owner of a 2005 901 CDX. My issue is a horribly sluggish hole shot. It's painful. Plows water for 10 to 15 seconds. If I have a third passenger, I need to have the third buddy crawl up front to help get the bow down. I've been on other bass boats, and haven't observed such a sluggish start from other rigs. I read that the 901 CDX is a heavy hull, and perhaps a bit under-powered even with 200 ponies. I'm running the Tempest 25 pitch, three blade on a 2005 Optimax 200 2-stroke. PVS holes appear to be medium. Once on plane, I get decent top end speed (at least decent enough for a first time bass boat owner, not comfortable getting too crazy!), but am only spinning 4200 rpms WOT. Even on calm water and 10 - 12 miles of open water in front of me, I can't get over 4200 rpms even playing with the trim, unless of course I cavitate the motor.

    After a bunch of research, here's more that I can offer:

    Center of shaft (cone?) is approximately 9" below the pad. From what I read, this is likely far too low.
    I have absolutely zero rooster tail (not that this is important to me) but again suggests that my motor is too low.
    I have no adjustable jack plate. Motor is mounted to a pseudo jack plate, but there's zero adjustability.
    Motor has five mounting holes, and is mounted on the second from the top (meaning it's almost as low as it can be).
   I had my wife bury the Hot Foot to the floor, and while looking under the cowling, I can confirm that the Hot Foot is set up correctly, and the throttle is indeed buried all of the way. I was hoping for a quick fix. . . .

    I've tried a buddy's High Five 23 point prop. Very good hole shot, approx 4800 rpms, but I dropped 20 mph on the GPS. I tried a few other props last fall that I could bum from friends, after picking up my new baby, but was never able to hit the magic 5200 rpms.  I wasn't able to try a 24 pitch prop.

    Will completely pulling out one or more of the PVS plugs help enough? What about dropping to a 24-pitch prop, either 3-bladed or 4-bladed? Or is it safe to assume that my motor is just too low? Would mounting it on the bottom of the five mounting holes help enough, thus raising the motor approximately 1.5"?  Or am I looking at installing a jack plate, either manual or hydraulic?

    I'm a first time bass boat owner, and will welcome and relish the advice from those of you who are veteran owners.  Even better if a veteran Nitro owner can lend me a few minutes.  On the plus side, it's just AWESOME to fish out of, far better than my wife's old Lund boat!  Thank you for your time.

[Bassinkorea]

Welcome to the forums Borkman, glad to have you here. And welcome to the fun of owning a bass boat 

We have a bunch of very knowledgeable folks around here (me not being one of them) that will be able to give you some great advise to get you in the right direction. However, my first thought is that your motor is wayyyy to low at 9 inches.

You will get some good solid info soon, so stick around and have a look around the rest of the forum whilst you are waiting   

[Bud Kennedy]

I agree that your motor is too deep if indeed it is 9" below pad.  A good place to start would be to move the motor that will give you approximately 3.5" below pad as a starting point.  Since you don't have an adjustable jack plate I realize this is a bit of a job but if you can get the right hole to use and get close to the target number, then we would like to hear your numbers again including time to plane and WOT.  Any description about how you adjust your trim might also be helpful.

I have a 91 vintage 300 series ranger with a 150 that turns a 4 blade and I can turn about 5800 rpms.  At one time my motor was also way too deep and it waddled around like a whale.  Don't have that problem any more.  The only change I made was re setting the motor to 3/5" below pad

You likely will have to make multiple changes to improve things but make the changes before going into the swap a prop routine that many folks do.  With a 200 hp motor you got plenty of horses and while I do suspect your prop may be a bit heavy the prop to pad has to happen  first.  Also pay attention to your water pressure during these adjustments.  You should be pulling at least 20lbs at wot and maybe up to 30 lbs is possible.  Don't let it drop below 10 as that would mean you are not getting enough water to cool the motor.  Let us know how you make out.  In case you need it I have attached a drawing of the correct way to measure prop to pad.

[Borkman]

Thank you Bud and Korea, sure appreciate the quick response.  You aren't telling me anything that I didn't fear.  I was hoping for a quick fix, like a new prop, but feared that I'd need to raise my motor more than the 2" allowed in my current setup.  Believe it or not, as a newbie, I actually measured the motor height as your picture describes.  Motor skeg actually hits the ground when trimmed down.  It really is that low!

So, in order to raise the motor more than about two inches, I think I may need a jack plate.  Is there a clear reason to spend the extra money on a hydraulic Atlas, or will a manual jack plate more than meet my needs? 

For clarification, I do not intend to get back into the bass tournament scene.  Tried that 30 years ago when living in Virginia.  I'm just an advanced recreational smallmouth angler, looking for a bit better performance from my first investment into a bass boat.  So I'm not sure I need to trick out this baby for maximum performance on the water.  Thank you again!

[Bud Kennedy]

If it was me I would go with a simple manual jackplate.  I fish the same waters most of the time and I am not interested in super high performance that requires me to want to make multiple changes.  I have only had manual jack plates in my 40+ years of bass boat ownership.  My current jack plate has only been moved once in all the years I owned it and that was because the original setting was way too deep.

I am not saying that later you may want to fancy things up a bit but my experience has been if it works then don't mess with it.  You will be amazed how much a proper set up will improve things quickly.  I can't imagine not having a jack plate just in case I need to do a re power or something like that.  Otherwise I will never move it as long as I get solid performance like I get now.  My current rig is 30 years old including the motor.  Someday however the motor may need replaced.  If it does then the jack plate will make the new set up much easier.  I just hope I don't have to find out if you know what I mean.

[Borkman]

Bud, my apologies. . . .  apparently I'm not as sharp as I imagine I am . . .  I put the rig on a concrete floor, and put a bubble level on the trailer and the lower unit.  And per your diagram, I am at 3 inches!  Not sure just how I got 9" before, but now I feel stupid!

So now the question is, am I too shallow?  I can only drop the motor about 1/2" to the lowest setting.  Or should I be looking at those PVS holes in the Tempest prop, or even trying a new prop, e.g. 24 pitch?  Or should I still just suck it up, stop whining, and drop the money into a manual jack?

I sure appreciate your wisdom and willingness to assist. 

[rjn cajun]

Welcome Borkman-

I have the same Optimax as you however on a different boat. I'm running a 2005 Ranger Reata 190vs FS. I have more of a V-hull vs your bass hull. I have done a lot of prop experimenting this Spring on my boat looking for that top RPM for our motors which is 5750. I use a 23p highfive for pulling tubes. That prop gets me 57mph at 5450. I have tried a 24p Trophy Plus with different size PVS. That prop would blow out on take off and I could only get 50mph at the 5750 RPM. I'm curently running a Fury 4 at 5550 RPM at 64mph and a very nice ride. I just purchased a 24 Tempest Plus yesterday I will be trying in a few days. I most likley need a 23p but like I said I'm experimenting. I to have no jackplate so before I spend the $$ for a jackplate I'm experimenting with props then I will decide if I want or need a jackplate. Every boat is different so you will need to just experiment with your setup. Like others have said this board has a wealth of knowledge. Take a little in from everyone and you should have a good starting point. There is most likley someone here with that same setup. Hope this info gives you a place to start and again welcome aboard.

[Nutt]

To start, I would add a manual jack plate.  I cant believe it doesn't already have one.  Check out Hydro Dynamics.  They make a good jackplate. 

[Bud Kennedy]

Before you had mentioned that your skeg was just about on the ground..  Is that still the case?  If you are at 3" below pad I would find that very very unusual.   If indeed you are at 3" I would not invest in a jack plate at this time but you have nothing to lose by working with the vent holes.  If you have a profesional prop shop near you are a very respected motor mechanic they may be able to offer some advice about what prop you should be using.  The problem you report is very significant when you state you can only get 4200 rpm.  That is a real problem and maybe just maybe you also have a lower unit or motor problem that needs to be checked out.  Plain and simple something ain't right.  As you probably know there are many other things that can be causing the problem.  Would be interesting to see a computer readout on the overall health of the motor and also the results of a lower unit inspection just to be sure.  You may get lucky and find it is something simple like a fuel pump or dirty injectors or perhaps even a not so cheap power pack. 

If you check some old posts on Ultimate Bass you will see I too experienced some of the same issues but my motor is a carb motor and the carbs had a problem but so did the encoder  I spent well over $2K just having the tech go over each and every thing on the motor.  At that time I could not get any rpms either and the problem was a combination of many things among which was incorrect jets in the carbs plus cracked bowls etc etc.  May be time on your motor for a full analysis and check up by a reputable shop with the right tools and testing capability.  I am afraid you have something else going on.

Motor gremlins can happen to all of us and can be a real problem to find the 'true' problem(s)

Who knows you may get lucky and it will be some simple and not expensive problem.  so many things are possible at this point since you set up appears to be ok.

[Borkman]

Attached are a few pics, one showing the motor mount holes, and I can lower in one hole, or raise it up three holes.  The second and third show the motor relative to grade.  Both the motor and the boat are level using a bubble level. 

Motor was inspected last year prior to purchase.  Mercury mechanic reported that the motor had 5.2 hours on it, and everything checked out:  Compression, injectors, etc.  Mechanic said it was still brand new and not even thru the break-in period.  I observed the hole shot issues on her maiden voyage on Rainy Lake. 

We have the Prop Shop locally.  They work on props nationally.  Problem is that I live in walleye country.  The majority of the anglers up here look at smallmouth the same as most folks elsewhere view carp.  Just trash fish to them.  They flat out told me that they couldn't help me with setting up and tweaking out a bass boat.  That led me to joining my first ever forum.  This is all new to me. 

I made some calls to Mercury dealers down south in MO and TX.  General consensus was to try a few demo props to see if I could find one that works.  Was recommended to try the Tempest 23 pt or the Fury 4 - 24 pt.  Problem is that no one up here in Duluth has those props to demo.  Maybe I'll try the Twin Cities or a dealership around Mille Lacs Lake. 

I think on Saturday, I'll yank out one or two of those vent hole plugs, and the wife and I will head out   fishing and see what the performance is.  I can report back afterwards.

If I can't get anywhere with demo props, maybe I'll take in the rig and get a computer analysis done and resurrect this thread later in the summer or early fall. 

Sure do appreciate everyone's input. 

[Bud Kennedy]

The pics you posted are inconclusive.  Cant really see a reference from hull to ground or from hull to center line of the prop.  I looked at the specs of this model and now I am curious what are your reference points on the hull that you identified as planning surface.  The pics indicate that you are still too deep on your prop but then again that depends upon your measuring points.  This is a deep vee hull and it appears the pads are on the outer edge of the surface and not in the middle or center.  The picture also indicates that your trailer is really really low to the ground and that is what may be creating the visual illusion for me.

Your boat appears to be equipped with all the standard stuff but a 10" manual jack plate was highly recommended.  This is a real puzzle without personal reference to your boat.  I understand your problem having a bass boat in that part of the world and finding experienced bass boat technicians and not folk who are just trying to sell a boat.  Keep looking and I hope you can find someone to help you determine the issues.

[Bud Kennedy]

FYI UB Member CraigP83 lives near International Falls and maybe he knows someone in that area who might be able to help.  You should send him a PM to see if he might be able to make some recommendations.

[Borkman]

Bud, given that you have been so helpful, I will gladly take whatever images you would like to see. 

The "jack plate" that I have is not adjustable.  There are bolts running thru, but no slide rail and no manual bolt that I can use to raise or lower the motor. 

I measured according to the image you posted, just below the drain plug to the floor, and from the floor to the center of the prop shaft.  The difference was 3 inches.  I will go and take a picture of the back end and upload in a subsequent post.  Perhaps that will help. 

Again, I sure do appreciate you helping a total stranger. . . .   

[Borkman]

Bud,  View of the presumed plate and the outboard.  Again, both the boat and motor have been leveled to a bubble level. 

Please let me know what you see or what you'd like to see.  And once again, thank you very much!

[Nutt]

Are you getting any bow lift, or is the nose staying low in the water? 

[Borkman]

Nutt, yes I am getting bow lift.  With three passengers, I need a passenger to head up front to get the bow down.  Otherwise I don't get on plane. 

[Bud Kennedy]

The quandry I still have is the fact you are only getting 4200 rpms  Clearly this is not good enough with the weight load you describe.  You boat has a big gas tank that when full is approaching 500 lbs of weight.  Now that weight coupled with the weight of three people and maybe even full live wells may be creating a weight distribution problem.  This however does not explain 4200 rpms.  I still believe that you are experiencing a motor issue to go along with potential prop issues or maybe even a lower unit issue.

[Borkman]

Bud, I've never completely filled the tank.  Just too expensive!  But I have had three passengers on multiple occasions, due to the HUGE front deck and ample real estate to fish from.  I've also never had a full livewell.  I don't do tournaments any longer, and I don't eat smallies. 

You make me sad.  I was hoping for a quick fix.  I'm pretty simple that way.  But you've talked me into taking it back in to a Merc shop and getting a complete diagnostics run on everything. 

Maybe in addition to popping out a few of those PVS plugs, I'll replace the spark plugs as well.  Maybe it's as simple as a bad spark somewhere, though the motor does purr and doesn't sound like it's missing on a cylinder.  It also doesn't shake like I'd expect a bent prop shaft to shake.  But, I'm no expert and I guess I'll pay to have an expert give me another look over.

I'll likely not be able to get an appointment for a few weeks.  Stay tuned. . . .  And thanks again!

[Bud Kennedy]

Thanks for the update.  I sincerely hope they give your motor a clean bill of health but I firmly believe it is the right thing to do.  When I was having motor trouble mine seemed to run well and would start easily but it just was not able to make rpms. Be sure to ask for a copy of the computer report.  It is a good thing to have in your motor files.  Whenever you can get an appointment we will anxiously await your report.

[Wizard]

A very heavy boat for a 19 footer. About 1700-1800 lb. if I recall. The 200 Opti was the top motor and Tracker sold them with a 150 hp. A friend had one with a 200 and it topped out in the mid 60's. I felt it should have a 225 hp. minimum on the back. The main problem was with a full tank of fuel. The tank carried 60 gallons (480 lbs) right on the ass end. The equivalent of 2 big anglers sitting behind you and laughing while you struggle to get on plane. With full back lockers and heavy consoles, the greatest weight is well rear of the boat's center. Some things you can do before jockeying the motor placement.
1) Only carry 20-25 gal. in the tank. Plenty for fun fishing.
2) Balance the boat. Shift weight from rear to front.
3) Don't fill the live wells before you have fish to keep.
4) Don't try to ease on plane. Stomp on the throttle like you would a cockroach.
Good Luck and don't try to re-power with a 225 unless you want the motor and transom laying on the highway.

Wizard

[Borkman]

Thanks everyone!

As suspected, I can't get my motor in to the Merc shop for a check up for two weeks.  So I'm doing a few things that I can do:

I'll replace the spark plugs, just in case
I'll replace the fuel filter, just in case
I just pulled one of the PVS plugs in the 25 Tempest Plus

However, when I was under the cowling, I noticed that the motor may be a 2.0 L?  Is that possible?  I thought the 200 Opti's in 2006 were all 3.0 L.  But on the serial number plate, it clearly says:

2006 200L OPTI
Max RPM  5750
HP 200  /  KW 147
LB  495  /  KG  225

If this is a 2.0 L, am I just expecting too much from this 200?  Should I be content with mid-50's gps?

I have an appointment, and have asked the Merc dealer to check compression, spark to all cylinders, I've asked for the computer print out on the diagnostics, and if everything checks out, have them review the accuracy of the Tachometer.  Having the tach inspected is 2 hours of labor ($105 / hr) doing a lake run.  Is there anything else I need to ask for?

This weekend, I'll take her out and see if the new spark plugs, new fuel filter, and one less PVS plug makes any difference in the world.  I do have a buddy with an engine hoist.  Is it worth dropping the motor down one set of holes, from 3" below pad to about 3 1/2" below pad, or should I check the other variables first prior to dropping to 3 1/2" below pad?

Further, to clarify for Mr. Wizard, I'm running only about 15 gallons of fuel in a 58 gallon tank.  My wife and I combined are just at 300 lbs.  Only weight in the back are empty livewells, three batteries, oil reservoir, fuel cell, and not much else.  Rods and tackle are up front.  I don't think I have too much tackle.  Does anyone?    I do stomp on the hot foot.  I'm hopeful that removing one of the PVS plugs in my 25 Tempest Plus will be the ticket.  I won't be re-powering with a 225.  Just not in the budget.  I'll just stick with the 200 until she kicks the bucket.  I'm not interested in being the fastest boat on Rainy Lake.  I just want her purring at peak performance.       

Again, I sure appreciate all of your time in helping a newbie to bass boats. . . .  respectfully, Borkman

[Bassinkorea]

However, when I was under the cowling, I noticed that the motor may be a 2.0 L?  Is that possible?  I thought the 200 Opti's in 2006 were all 3.0 L.  But on the serial number plate, it clearly says:

2006 200L OPTI
Max RPM  5750
HP 200  /  KW 147
LB  495  /  KG  225

If this is a 2.0 L, am I just expecting too much from this 200?  Should I be content with mid-50's gps?

What makes you think it is a 2.0 liter?
From the numbers you put above it looks to me like you have a 200hp 2006 Opti.

I have a 2005 150hp Opti and even that is a 2.5 liter.

[Borkman]

I was looking at the 200L, thinking it may be 2 L motor.  Guys at my local shop confirmed it's a 3.0L, and the L in front of the 200 indicates "200 hp, Long shaft".

I'll report back after I get her checked out at the doctors in two weeks.  Installing a new fuel filter after I change out of my work clothes. . . .

[Borkman]

I'm back from the doctor's. . . . Merc Opti passed with flying colors! Compression was good. Power to all six cylinders. They said there's nothing wrong with the actual motor. They did tell me that with the old Opti's, you can't just check the tach's rpms like you can with the new 4-stroke Yamahas. So the tach was not verified for accuracy.

New spark plugs and new fuel filter the other day. I did take it out last night to test the plugs and fuel filter. I also removed one of the three PVS plugs in my 25" Tempest. Actually, my hole shot now is acceptable. Much better than ever before, although I only had maybe 15 gallons in the tank. With my wife and I, and not a huge runway to test her out, I did get up to 4700 rpms and 52 mph gps.  I was trimmed a bit higher than I have in the past

I did take note of my water pressure, somewhere north of 12 but not at 15 at WOT. Not sure what this means.

So I guess that leaves me with either:

1) a fawlty tach, but I'm thinking I should still be getting better than 52 mph. Combined, my wife and I weigh in at 300 lbs;
2) Need to demo a 24" prop and see if that helps with rpms and mph;
3) Lower my motor from 3" below pad to 3 1/2". I have one hole to drop down. Merc guy said today that the #2 hole is the typical installation, and that was before he saw that I'm at the #2 hole, or;
4) Invest in a jack plate.\

Again, I'm very grateful for any advice. Thanks!

Borkman

[apenland01]

I don't know anything about the Nitro, but dropping the motor to 3.5 inches from 3.0 will decrease RPM, not increase them.  Also, if you don't have a jackplate, you'll be moving from 3.0 to 3.75, as those holes are 3/4 inch drop for each hole.

If your RPM on holeshot breakover isn't between 3,600-4,000, pull another plug out and test.  It won't help your top end WOT, but it will help your holeshot be more efficient.

You may simply be trying to turn too big a prop for the hull/motor combo.

As for your water pressure, that's probably fine, since your RPM's are so low.  If you were at 5,000 or more RPM, you would want to see north of 18-20, which is what would happen if you were moving faster.