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boatpi

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I’m no expert, but he’s reaching 4600 to 5000 RPM. no matter what the throttle position he’s getting the RPM out of the engine. He was running the same prop someone may be onto something here talking about the gear ratio, and that replacement out Drive.

that could be the issue. The actual RPM of the prop speed is what may have changed, the engine is still max RPM but the prop has reduced its RPM therefore the boat cannot reach the higher speed. Maybe Merc has a way to read the prop shaft speed that’s what it’s about I think.
 

JD D05

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I have had a boat my whole life. This isn't my first boat. I understand about weight, gas, temperature, etc.... my problem is this boat with this setup shouldn't have a top speed of 53 regardless of weight, temperature, or elements. I have never had to run a boat full throttle all the time.
What I'm really trying to find if anybody else out there has this same boat with a 600 mercury motor in it. I want to go back to nordic with other results from other owners.

Something is definitely off. I had a SS with the same motor different boat but still. I have owned 3 600SCI's current boat has 2 and have not come across this. I have had many codes putting it into Guardian but it was obvious.

Has it been hard to plane out? I also blew a stock XR with wrong prop with unexpected weight on the boat getting on plane. I snapped cruising but I know the damage was done getting going.
 
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petie6464

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Dang I knew Nordic cat bottoms are nothing to brag about but that's ridiculous.
 

Joe mama

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I would think Nordic would chime in. I’m sure they have heard about it by now. They are a stand up company and I’m sure they will figure it out. Nobody wants bad press.
 

boatpi

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Also take a look at your new outdrive is it the same casing or different internals. if someone put on a different lower (shorter) it would change the X dimension and therefore your prop position may be way out of whack.
 
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ToMorrow44

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ahhhhh i missed it had a blower.

still......since the supercharger is mechanically driven............you would make a little less boost as you are starting from a lower density atmosphere. this may not be the case if there is a blow off valve that is opening closer to sea level. if not.....a blower pulley change would be in order to make the factory boost level at high altitude.
There is a bypass valve to bleed off boost at lower Altitudes such that it’s supposed to make the same boost at altitude. That being said, even if it made the same boost number, power is still going to be down at higher altitudes. Gale Banks’ video about the boost gauge being dead where he explains this is a good watch, kinda long but good.
 

2FORCEFULL

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I have had a boat my whole life. This isn't my first boat. I understand about weight, gas, temperature, etc.... my problem is this boat with this setup shouldn't have a top speed of 53 regardless of weight, temperature, or elements. I have never had to run a boat full throttle all the time.
What I'm really trying to find if anybody else out there has this same boat with a 600 mercury motor in it. I want to go back to nordic with other results from other owners.
Here's where I would start, get on the mercury prop slip calculator...I would test the boat @ every 500 rpms and see what the slip is...could be just the wrong prop.. you have an air entrapment hull that probley doesn't pack ait till about 75 mph and so it needs a bow lifting prop and you probley have too much stern lift... also.... you should try a 24p prop for that elevation... you need good info to start..a 24p would do that...some get lucky and just get the right prop to start... most all will benefit from proper boat prop test,... when at speed where is it breaking water???? some time triming past where you think is too much is where it wants too run..i'd even try a 23p rev 4....but like I said ... find out why it won't rev
 

boatpi

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I believe my comment on prop speed and 2FF's suggestion are on target. Engine is getting RPM, somehow the prop is not or is slipping.
 

fishing fool

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Please read this first post..........

If he is on the rev limiter doing the same speed with a 26, 28 and 30 prop there is another issue........ This is not a "hull" "weight" issue...... Speed is a calculated number by rpm, drive and prop. If nothing changes with the motor and drive the speed should increase by going from a 26 to a 30 (yes there will be slip). This sounds more like a tuning (computer) or false data problem.




I would like here back from people that owed a nordic 29 deck boat. Im having alot of issues with speed for this boat . I have a 600 mercury racing motor and the xr racing drive with a 26 pitch. I have tried a 28p and 30p but nothing really changes on speed. This is a brand new 2020 boat. I can only get the speed up to 53 mph with 4 kids, wife, and myself. We total about 580 pounds altogether. We probably have another 400 pounds in all of the storage cabinets.
This boat went 79 mph with 40 gallons of gas in it and one person driving. Then it went 76 with full tank of gas and storage compartments all filled and one person driving. I was not doing the driving. The only time I've seen it over 60 is when I was at a lake with the elevation of 4600.
I would love to get some feed back of what motor you have in yours and speed you get out of it with just one person and then with people in the boat.
Thanks
 

2FORCEFULL

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60 mph @ 5000 rpms is 27 slip... sum ting wong...

one of the big things to consider when building a boat is what is the boat gonna be used for.... both sides of the transom need to match..most go to gether with just top speed as the factor...might need a drive spacer.... but like said... I'd get thane involved @ nordic
 

2FORCEFULL

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also, the 79mph is only 4% slip... that tells me that it's packing air about 75 mph.. so till you get to that spot you need more bow lift
 

2FORCEFULL

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Please read this first post..........

If he is on the rev limiter doing the same speed with a 26, 28 and 30 prop there is another issue........ This is not a "hull" "weight" issue...... Speed is a calculated number by rpm, drive and prop. If nothing changes with the motor and drive the speed should increase by going from a 26 to a 30 (yes there will be slip). This sounds more like a tuning (computer) or false data problem.
not quite grasshopper, an air entrapment hull needs wind force in the tunnel to perform...the stern lift is not a problem at 79 mph that it is at 60... another spec of info was the fact that he hit the builders wall.....boat won't go faster no matter what prop...that tells me to look at the drive height and prop lift..I pretty much had the same problem with the hallett with twins I had..but I did fix it...
 

2FORCEFULL

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Please read this first post..........

If he is on the rev limiter doing the same speed with a 26, 28 and 30 prop there is another issue........ This is not a "hull" "weight" issue...... Speed is a calculated number by rpm, drive and prop. If nothing changes with the motor and drive the speed should increase by going from a 26 to a 30 (yes there will be slip). This sounds more like a tuning (computer) or false data problem.
also. the boat went 79 mph till he loaded it
The boat has a great bottom.. what are you talking about?
it's called shit talking at a bench race... when you have nothing to add thats helpful, you just talk shit...
 

2FORCEFULL

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the bigest thing I learned while drag racing was test and tune.... I would do nothing differant but go run the boat and record info,..I would see where its breacking water...
next, I would take the boat back to where it did 79 mph ....then one step at a time see where it heads the wrong way...the other option is this,... say this is how I plan to run the boat...so rig it to perform at that need...a member here had a conquest w/ 525 power, struggled to get on plane and was slow,... wouldn't turn more than a 24p..but... it was all the weight he added
 

2FORCEFULL

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again... the drive needs to match power and intended use...every body want a shorter drive...
 

3.Slow

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Seems like we have this actual boat's numbers:

"This boat went 79 mph with 40 gallons of gas in it and one person driving. Then it went 76 with full tank of gas and storage compartments all filled and one person driving. "
True, those are the numbers that were given to the owner, but they can't be reproduced. I think he is just looking for other owners opinions on how their boat runs, what is their trim at, what are their tabs at, where are people sitting.
 

spectracular

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You mentioned that a new drive was recently put on. Any chance it is the wrong length and is either putting the prop too high or too low?
 

riverroyal

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one positive thing is that its a Nordic. They will get it you dialed in. Zero worries about that
 

Liberated

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There is nothing wrong with the boat. It's not the wrong gear ratio,,, It's not the wrong X dimension, prop, weight, people in the boat, etc, etc , etc. Since the boat runs bitchen one day and then sluggish the next day. It pretty obvious it's a electrical glich with the engine. Been thru this a hundred times. As always with a Nordic it will get resolved when we have the boat back.
 

riverroyal

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There is nothing wrong with the boat. It's not the wrong gear ratio,,, It's not the wrong X dimension, prop, weight, people in the boat, etc, etc , etc. Since the boat runs bitchen one day and then sluggish the next day. It pretty obvious it's a electrical glich with the engine. Been thru this a hundred times. As always with a Nordic it will get resolved when we have the boat back.
John, Im trying to buy the slow boat at a discounted rate. Your ruining my chances..... cheers
 

Duramax

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also, the 79mph is only 4% slip... that tells me that it's packing air about 75 mph.. so till you get to that spot you need more bow lift
You wont get 4% slip from that drive and hull. 7-10 is probably about right.
 

Duramax

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What do other 29's run with a 600? I would think you would be safely in the 70's with that boat, and it looks like a wave crusher. I don't want to be that guy, but drop it off and tell them you do not want it back until it is correct, otherwise you take further action. You have more patience than I do. I'm sure you waited a long time for your build, only to get a big fucking slap in the face with 50mph!?
 

RiverDave

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What do other 29's run with a 600? I would think you would be safely in the 70's with that boat, and it looks like a wave crusher. I don't want to be that guy, but drop it off and tell them you do not want it back until it is correct, otherwise you take further action. You have more patience than I do. I'm sure you waited a long time for your build, only to get a big fucking slap in the face with 50mph!?

Well he said it ran 80 and now it doesn’t.. something changed In there.. could be a problem, or it could beadding a ton of weight.. who knows just from this thread.

Nordic has said they will look at it and fix it right above your post.. I’m a believer in catching flies with honey, not vinegar
 

fmo24

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Could there be water trapped somewhere in the hull? I’ve seen kids playing with the shower in the bow squirting a ton of water in a boat
 

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Is it possible the wrong octane fuel was put in the tanks? Plugged fuel filter?
 
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