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496 remap

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Hello,
I have a 1997 DCB 24 extream with a 496. I was thinking about maybe getting the computer remapped for a little more. What do you guys recommend? I have run my boat to 69 mph with 26 p prop, my motor only seems to turn 4200 rpm.
 

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NicPaus

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Have your prop labbed. I have a 496HO and with stock 26b1 can not hit rev limiter but with the labbed 26 I do at 73 mph.
 
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What company do you recommend to do that? How about going to a different pitch size. What did it cost get it labbed


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NicPaus

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Try a 25p from Jacos marine. I have searched for a used 1 but not a common size. One of these days I will order 1.
 

NicPaus

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My prop was labbed by Hill propeller.
 

Lavey 29

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you should be at 4800 rpms at WOT for the 496 mag and 5000 rpms for the 496 mag HO. I would get that dialed in first and foremost. There is many reasons other than a prop and or wrong pitch prop for not reaching max rpms. Engine mechanical issues and or fuel pressure related and or engine in guardian mode and or sensor related and or fuel injectors contaminations especially if you have the GEN 3 cool fuel. Anyways a jist of info. I would not mess with the tune for a OEM stock 496. I would mess with props and placement of weight for a balanced hull and weight savings to gain speed.
 

Singleton

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I did it and had it removed
My 496HO after remap ran very rich and caused more soot at higher RMP’s. While I enjoyed the added mid-range punch and top end, it was not worth the unhappy wife and the black feet it caused getting into boat.

Max RPM of a 496HO is 5200, after Whipple remap goes to 5450.
 
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you should be at 4800 rpms at WOT for the 496 mag and 5000 rpms for the 496 mag HO. I would get that dialed in first and foremost. There is many reasons other than a prop and or wrong pitch prop for not reaching max rpms. Engine mechanical issues and or fuel pressure related and or engine in guardian mode and or sensor related and or fuel injectors contaminations especially if you have the GEN 3 cool fuel. Anyways a jist of info. I would not mess with the tune for a OEM stock 496. I would mess with props and placement of weight for a balanced hull and weight savings to gain speed.

Thank you. I had the motor scanned and everything came out perfect . They said everything where it should be.


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NicPaus

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Thank you. I had the motor scanned and everything came out perfect . They said everything where it should be.


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You headed to the river by chance this next weekend. I will be in Parker. Have a few props you can try.
 
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Hello, I am not unfortunately getting some interior stuff taken car of. Right


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merc_400r

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have you played around with props? Was it able to hit redline before?
 
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have you played around with props? Was it able to hit redline before?

To be honest I never really paid close attention till end of season last year. I always had my 3 year old and 1 year old on it. Last trip I was with just a buddy.


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NicPaus

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My bet is a 26 is to much just like my boat. It will spin it to 4400 or so. With the labbed 26 light load I can hit 5200 and set off rev limiter beep.
 
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My bet is a 26 is to much just like my boat. It will spin it to 4400 or so. With the labbed 26 light load I can hit 5200 and set off rev limiter beep.

I think my best bet is prop. I need to find someone local and get it a try


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Lavey 29

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rev limiter comes it a 5150 rpms for the HO and 4950 for the MAG. Stay off the rev limiter it is hard on the valve train among other things.

The stock OEM 496 has ZERO hp gains after 5 K anyways. Also nothing is forged internally and the valve springs and heads are nothing to write home about.
 

farmo83

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Alexi and Raylar are the only guys I know of with proven setups for the 496.
 
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rev limiter comes it a 5150 rpms for the HO and 4950 for the MAG. Stay off the rev limiter it is hard on the valve train among other things.

The stock OEM 496 has ZERO hp gains after 5 K anyways. Also nothing is forged internally and the valve springs and heads are nothing to write home about.

I’m just want to see more RPM then 4200


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Singleton

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Alexi and Raylar are the only guys I know of with proven setups for the 496.

@BoostPower and Whipple have ECU re-mapping. Also https://www.simonperftech.com/ out of El Cajon does some work as well. I would only have Alexi touch a Raylar kit Install, he walks you through everything and is extremely knowledgeable on what else needs to be addressed.
 

BoostPower

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@BoostPower and Whipple have ECU re-mapping. Also https://www.simonperftech.com/ out of El Cajon does some work as well. I would only have Alexi touch a Raylar kit Install, he walks you through everything and is extremely knowledgeable on what else needs to be addressed.

We like those kits and of course we add our little menu of items [emoji41]


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merc_400r

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To be honest I never really paid close attention till end of season last year. I always had my 3 year old and 1 year old on it. Last trip I was with just a buddy.


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was wondering if its a sudden change that is causing it. Sounds like you would gain from playing around with some props to see if you can get where you want to be. Then if you still want more look into engine mods. Just feels like you are not maxing out your current configuration.
 

Singleton

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Hello,
I have a 1997 DCB 24 extream with a 496. I was thinking about maybe getting the computer remapped for a little more. What do you guys recommend? I have run my boat to 69 mph with 26 p prop, my motor only seems to turn 4200 rpm.

now that I read this again, check your spark plug wires.
i had a similar issue and one of my wires was laying against exhaust manifold, causing a short
also check tach, gauge might be off
 

Ladsm

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now that I read this again, check your spark plug wires.
i had a similar issue and one of my wires was laying against exhaust manifold, causing a short
also check tach, gauge might be off

I had this exact same issue, plug wire shorting out on Exh Manifold. Really showed itself in the moring when engine was cold
 

LargeOrangeFont

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If you haven't changed the plugs.. change them while you are down there.
 

Lavey 29

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Like I said in my first post get to max rpm range first as you might have a mechanical issues and or fuel delivery issues and or are in guardian mode in which the 496 is always known to have sensor issues. Always. Raising rpm limites in the PCM 555 is going to do nothing period for you if you can not even get to max rpms to begin with.
 

Lavey 29

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they have junk spark wires. that are so over priced thru Mercruiser. Let me know if anyone needs wires instead of the mexico wires merc uses. Even merc racing engines use crap mexico wires
 
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they have junk spark wires. that are so over priced thru Mercruiser. Let me know if anyone needs wires instead of the mexico wires merc uses. Even merc racing engines use crap mexico wires

What wires do you run?


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Lavey 29

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I have them all made here in the USA by Moroso exclusively for me, matched lengths for marine engines - correct boots and so on. The wires come 2 different ways --- 350 ohms per ft and performance wires 40 ohms per ft for all marine engines including Merc racing engines. Working on 15 ohms per ft as well. I am in the process of doing my own marine parts even impellers and many more parts all made here in the USA. I have been doing this a very long time.
 

Mcob25rg

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I’m interested in the wire set for an HO. 2004 in a Nordic Rage, just did the plugs, were original, so I’m sure the wires are also. 440 hours, but it’s running great. By the way, factory Bravo I 26” right at 5,150 at WOT, 72 MPH, GPS
 

Heylam

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We are offering a lot of complicated solutions to a simple problem. Drop 2" in pitch on the prop and see what happens. My guess is you will be pleased.

Common sense right here.
 
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Does it matter between left hand prop and right hand prop?


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I actually have a left hand and my shop said I should have a right hand .


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HBCraig

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I have the same hull, Ultra 247 with an HO.

I have a labbed 26 and can hit right at 5000 rpm.
 

HubbaHubbaLife

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I'm having some recent issues losing some power on my 496HO around 3-4K rpm.... feels like missing some umph and miss firing a bit. It never stalls around docks and I ran some fresh 91 octane fuel through this weekend but still occurring. Its got 530 hours and I had the 100 hour Mercury service done at 400 hours. Any ideas?
 

Trash

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I'm having some recent issues losing some power on my 496HO around 3-4K rpm.... feels like missing some umph and miss firing a bit. It never stalls around docks and I ran some fresh 91 octane fuel through this weekend but still occurring. Its got 530 hours and I had the 100 hour Mercury service done at 400 hours. Any ideas?

Clean and flow test your injectors.
 

tbults88

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they have junk spark wires. that are so over priced thru Mercruiser. Let me know if anyone needs wires instead of the mexico wires merc uses. Even merc racing engines use crap mexico wires
What kinda wires do you run?
 

02HoWaRd26

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I have them all made here in the USA by Moroso exclusively for me, matched lengths for marine engines - correct boots and so on. The wires come 2 different ways --- 350 ohms per ft and performance wires 40 ohms per ft for all marine engines including Merc racing engines. Working on 15 ohms per ft as well. I am in the process of doing my own marine parts even impellers and many more parts all made here in the USA. I have been doing this a very long time.


Explain the difference in the variance of ohm per foot? Seems a huge variance with one set at 350o per foot vs 40o per foot.
 

Lavey 29

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the factory Merc wires one can ohm test those and see 1000 to 4000 ohms per ft after little use. 350 ohm per ft is below most oems wires especially for marine engines. All this can be verified with a good ohm meter. Also the OEM wires are made in Mexico. and tech speaking 6.75 mm in diameter. Thats very thin insulation around the inner wire core itself. I have 40 ohm per ft wires as well.

What one wants in wires especially for marine efi is RFI and EMI suppression . Also wires and boots that can HANDLE GAS FUMES 24 /7 because that whats your engine and components are exposed to GAS FUMES 24/7. Also many boaters charge their batteries for months while sitting - one of the worst things you can do - charging batteries in an enclosed engine compartment is filling it with sulfuric acid that the battery is releasing while being charged. This is hard on rubber parts as well.
 
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HubbaHubbaLife

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Just to add, low flowing / partially clogged injectors will make the motor lay down on the top end and cause subtle misses like you mentioned.
Just a note for ya..... this thread had gone dormant ..... my issue back in 4/20 proved to be injectors clogged with paint and this was all shared on a thread I started back then on RDP. You were correct in your diagnosis and wanted you to know I appreciated your input when I was flailing around searching for mechanical help. Boat sold and happily ended out in Kona, Hi with happy new family.
 

SBMech

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the factory Merc wires one can ohm test those and see 1000 to 4000 ohms per ft after little use. 350 ohm per ft is below most oems wires especially for marine engines. All this can be verified with a good ohm meter. Also the OEM wires are made in Mexico. and tech speaking 6.75 mm in diameter. Thats very thin insulation around the inner wire core itself. I have 40 ohm per ft wires as well.

What one wants in wires especially for marine efi is RFI and EMI suppression . Also wires and boots that can HANDLE GAS FUMES 24 /7 because that whats your engine and components are exposed to GAS FUMES 24/7. Also many boaters charge their batteries for months while sitting - one of the worst things you can do - charging batteries in an enclosed engine compartment is filling it with sulfuric acid that the battery is releasing while being charged. This is hard on rubber parts as well.

Resistance is not a measure if they have been in use (although a very high resistance wire can not fire - indicating a break internally), it is a measure of the way they are constructed to match the ignition coil/s.

If you run low resistance wires on a system designed for 2k, 4k etc you will damage the coil/s fairly quickly leading to a failure.

Everything in ANY ignition system is designed to handle GAS FUMES....it's the environment they were designed to live in?

But yes, crap parts can certainly deteriorate faster than quality/factory parts...YMMV.
 
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