New out of the box carb setup?
+ Reply to Thread
Page 1 of 2 1 2 LastLast
Results 1 to 14 of 21

Thread:
New out of the box carb setup?

  1. #1
    Senior Member Jetdream'n's Avatar
    Join Date
    Sep 2009
    Location
    Concord, NC
    Posts
    333

    Question New out of the box carb setup?

    I got no responses on this in the Dyno section so I'll try posting it in here....

    I'v been in search a pair of 750's to replace my 660'cs. They have done the job and for the afternoon WOT lake racing they work but, not the greatest on gas, idling is not great, would like better throttle control through out the rpm range and looking for over all better performance . So, a buddy of mine got me a killer deal on two of these. Not the best out there for a TR set up but none better for the price.
    https://www.holley.com/products/fuel...arts/0-76751RD



    Ive got the mounting plate adapters, fuel lines/fittings and sideways linkage on the way. Also in the proccess of removing the choke plates and linkage. Most of my carb set up experience has been with either a single DP or pairs of inline single inlet on TR set ups.
    My question is:
    Will I need to do any thing else to them right out of the box to get me up and running? The sideways mounting set up has got me a little worried. I know it will take time testing to get things perfect but, right now Im looking to just get on the water.


    19ft CP gull, set back Berk pump
    10:01 540 bbc 720ish HP
    119cc Alum heads
    Hyd roller
    647 Intake .647 Exhaust
    248 Intake / 254 Exhaust duration
    @ .050 - 112 degree lobe sep
    Victor TR
    MSD 6al


    Thanks

  2. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  3. #2
    Senior Member
    Join Date
    Dec 2007
    Location
    Newbury Park, Ca/Mohave Valley, Az
    Posts
    8,168

    Default No..

    No, you should be able to bolt them on, set your idle speed and go.... Once it's up and running you MAY need to fine tune the set up, but the jetting will likely be close enough unless you're running against a clock, which may take some jetting etc etc to get every ounce of power... But, yeah, they'll work right outa the box...
    Ray
    LOUD BOATS SAVE LIVES

  4. #3
    Senior Member
    Join Date
    Feb 2008
    Posts
    5,829

    Default

    In my opinion you would be better off getting two carburetors made for a tunnel ram.
    The calibration throughout the range should be better and unless you like to work on carburetors there may be a lot of tuning to do.

    Remember, most carburetors are generally designed to pull all the air through one carburetor and calibrated as such. Tunnel ram, blower and alcohol carburetors
    have been calibrated to work for their specific purpose.
    Tunnel ram carburetors have only half the air running through each carburetor and the air flow volume is different.
    The pictured carburetor will probably work, but I don't think it will work as well as one designed for a specific purpose.

  5. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  6. #4
    Senior Member PE 340's Avatar
    Join Date
    Aug 2013
    Location
    LHC,AZ
    Posts
    432

    Default

    Quote Originally Posted by jimsplace View Post
    Tunnel ram carburetors have only half the air running through each carburetor and the air flow volume is different.
    Not true. A 1050 CFM designed for a tunnel ram flows the same as a 1050 CFM designed for a single application. NOT HALF

  7. #5
    149 BGJ-Willis Power 540 willis's Avatar
    Join Date
    Feb 2008
    Location
    Gardena, CA
    Posts
    525

    Default Flowed - Calibrated

    Quote Originally Posted by Jetdream'n View Post
    I got no responses on this in the Dyno section so I'll try posting it in here....

    I'v been in search a pair of 750's to replace my 660'cs. They have done the job and for the afternoon WOT lake racing they work but, not the greatest on gas, idling is not great, would like better throttle control through out the rpm range and looking for over all better performance .
    19ft CP gull, set back Berk pump
    10:01 540 bbc 720ish HP
    119cc Alum heads
    Hyd roller
    647 Intake .647 Exhaust
    248 Intake / 254 Exhaust duration
    @ .050 - 112 degree lobe sep
    Victor TR
    MSD 6al
    Thanks
    August 16, 2014

    Hello People

    JD

    I have tried to do the same thing you are doing, make a set of carbs work, “out of the box”.
    There would always be something that wasn’t just right and the carbs would start fine, idle good, go full throttle, hesitate on part throttle, and bog when re-throttled.
    I must have purchased half the store before I had my carbs flowed/calibrated for the application.

    After the shop calibrated them, the boat was right on time from part throttle to full with no issues.
    Do yourself a favor and send / take them a shop that flows/calibrates.

    You will have more fun, end the frustrations- - -

    I'm in So. Cal, so I use C & J Engineering,

    Willis
    Last edited by willis; 08-16-2014 at 04:27 PM.

  8. #6
    Senior Member
    Join Date
    Feb 2008
    Posts
    5,829

    Default

    Quote Originally Posted by PE 340 View Post
    Not true. A 1050 CFM designed for a tunnel ram flows the same as a 1050 CFM designed for a single application. NOT HALF
    Sorry, I wasn't clear with what I posted.
    I meant that when two carburetors are being used, each carburetor would only be flowing one half of what air
    the engine requires, as compared to a single carburetor where all of the air is pulled through one place.
    You're correct that a 1050 will flow 1050 regardless of whether it is designed for a tunnel ram or for a single carburetor usage.

    My intent was to point out that the air signal is less for each carburetor when using two and the calibration would need to be different.
    Nearly all of the material written emphasizes the importance of selecting the correct carburetor for its intended usage.

  9. #7
    Senior Member nosfomoco's Avatar
    Join Date
    Dec 2009
    Location
    Sac, Ca
    Posts
    136

    Default

    I just bolted mine outa box( not tunnel ram special carbs) just stock 750dp holleys. The only thing was had to make sure linkage was in synch. I also later changed to 4.5 power Valves to lean it out a little on midrange. Bur they always ran and worked perfect.

    Sent from my RM-917_nam_usa_214 using Tapatalk
    1978 Eliminator Sport Cruiser 20.5ft BBF 460!

  10. #8
    Senior Member Boat 405's Avatar
    Join Date
    Dec 2007
    Location
    San Diego, CA
    Posts
    3,732

    Default

    Quote Originally Posted by willis View Post
    August 16, 2014

    Hello People

    JD

    I have tried to do the same thing you are doing, make a set of carbs work, “out of the box”.
    There would always be something that wasn’t just right and the carbs would start fine, idle good, go full throttle, hesitate on part throttle, and bog when re-throttled.
    I must have purchased half the store before I had my carbs flowed/calibrated for the application.

    After the shop calibrated them, the boat was right on time from part throttle to full with no issues.
    Do yourself a favor and send / take them a shop that flows/calibrates.

    You will have more fun, end the frustrations- - -

    I'm in So. Cal, so I use C & J Engineering,

    Willis
    I'll agree with Hello People, C & J does a great set of carbs. He has done every set I've got.
    Boat 405.

  11. #9
    just a ski boat with bark Carnivalride's Avatar
    Join Date
    Jan 2008
    Location
    Derby, Kansas
    Posts
    2,811

    Default

    Quote Originally Posted by nosfomoco View Post
    I just bolted mine outa box( not tunnel ram special carbs) just stock 750dp holleys. The only thing was had to make sure linkage was in synch. I also later changed to 4.5 power Valves to lean it out a little on midrange. Bur they always ran and worked perfect.

    Sent from my RM-917_nam_usa_214 using Tapatalk
    I'm running a pair of 750dp too but I also leaned the IFR circuits a of 30%, leaned jetting 3 sizes all the way around. Also modified discharge nozzles 31/32 if I remember right. Will they run out of the box, sure they will. Are they anywhere close to optimum I'd say no 95% of the time. Maybe I get a little carried away but I want my boat to run as well as it can for what it is.

    Just my $0.02
    Quote Originally Posted by gn7 View Post
    Carnivalride, you really need to find some other hobby. You have no talent for this boat thing

  12. #10
    Senior Member Jetdream'n's Avatar
    Join Date
    Sep 2009
    Location
    Concord, NC
    Posts
    333

    Default

    I agree 100% with you guys about turning them over to someone who's profession is knowing the proper way to set them up. This will be the plan this coming off season. Got a trip this coming weekend so, trying to just make them work good enough for now with minimal issues.

  13. #11
    Senior Member Jetdream'n's Avatar
    Join Date
    Sep 2009
    Location
    Concord, NC
    Posts
    333

    Default

    Also, what about the secondary linkage? Should I mess with them to get it closer to a 1 to 1 ratio or leave it at the factor set up?

  14. #12
    just a ski boat with bark Carnivalride's Avatar
    Join Date
    Jan 2008
    Location
    Derby, Kansas
    Posts
    2,811

    Default

    Quote Originally Posted by Jetdream'n View Post
    Also, what about the secondary linkage? Should I mess with them to get it closer to a 1 to 1 ratio or leave it at the factor set up?
    I thought you wanted drivability and some cruising economy? If that's the case leave the progressive link and power valves.
    Quote Originally Posted by gn7 View Post
    Carnivalride, you really need to find some other hobby. You have no talent for this boat thing

  15. #13
    Glendale Arizona Squirtcha?'s Avatar
    Join Date
    Jan 2008
    Location
    Glendale Arizona
    Posts
    2,368

    Default

    Quote Originally Posted by Jetdream'n View Post
    Also, what about the secondary linkage? Should I mess with them to get it closer to a 1 to 1 ratio or leave it at the factor set up?
    If you're gonna do that, you might as well put the 660's back on.

  16. #14
    Senior Member Jetdream'n's Avatar
    Join Date
    Sep 2009
    Location
    Concord, NC
    Posts
    333

    Default

    Quote Originally Posted by Carnivalride View Post
    I thought you wanted drivability and some cruising economy? If that's the case leave the progressive link and power valves.
    Thats forsure what I'm wanting however, Im very pleased with the power my old set up was making. Being able to run them right out of the box would be ideal. I'm just looking for the best all around lite skill set up for cruising and yet still be able to deliver during a hard pass or racing scenario . Not looking to make too big of a step backwards in raw performance just to save gas......
    Then all of a sudden Im run'n mufflers, haul an ezup,the dog, kids and the cooler around. Well maybe the dog....Thats what the wifes pontoon's for.
    Last edited by Jetdream'n; 08-18-2014 at 11:34 AM.

+ Reply to Thread
Page 1 of 2 1 2 LastLast

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Please select your insurance company (Optional)

Log-in


Tags for this Thread

Digg This Thread

Posting Permissions

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
  •  
 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95