Surge at WOT
+ Reply to Thread
Results 1 to 14 of 14

Thread:
Surge at WOT

  1. #1
    I'm No Expert Shaun's Avatar
    Join Date
    Feb 2008
    Location
    San Clemente, Ca
    Posts
    3,138

    Default Surge at WOT

    Since getting the new motor in my boat i've had a surge when mashing the gas from a idle or slow cruise. Before the boat wanted to jump out of the water so i figured it was caused by the pump being loaded/unloaded but i no longer think that. When cruising or launching and then getting off the throttle it doesnt do it. It's only when i mash and stay on the gas. I beleive it was RCB19 who recommended that i get a special floats that where thinger at the rear of the bowl so that when the fuel came up the side it wouldnt shut off the needle. Sombody else recommended getting carb plates with angle to them. Wondering what some of you guys may think it happening.

    http://unix-scripts.com/hb/uploads/2010-07-10-1.avi
    http://unix-scripts.com/hb/uploads/2010-07-10-2.avi
    http://unix-scripts.com/hb/uploads/2010-07-10-3.avi
    http://unix-scripts.com/hb/uploads/2010-07-10-4.avi
    http://unix-scripts.com/hb/uploads/2010-07-10-5.avi
    http://unix-scripts.com/hb/uploads/2010-07-10-6.avi

  2. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  3. #2
    gn7
    gn7 is offline
    Senior Member gn7's Avatar
    Join Date
    Jan 2008
    Posts
    25,975

    Default

    Shaun, if the surge comes alittle while after you mash it, I doubt its the floats. That would show up almost immediately after you punched it. What regulator are you running. And what pump.



    100% free webcam site! | Awesome chicks and it is absolutely free! | Watch free live sex cam - easy as 1-2-3

  4. #3
    Senior Member GT Jets's Avatar
    Join Date
    Jun 2008
    Location
    Morgan Hill
    Posts
    2,234

    Default

    Shaun, I agree with gn7, it sure sounds like a starvation issue......

    Almost like you are aerating the fuel pump (would mimic a vapor lock)...
    GT


    Quote Originally Posted by Quickjet View Post
    Put a 300 on the back of it, Flywheel it and a nosecone. $15,000 later you'll have a 65 mph pile of shit......

  5. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  6. #4
    I'm No Expert Shaun's Avatar
    Join Date
    Feb 2008
    Location
    San Clemente, Ca
    Posts
    3,138

    Default

    Mallory Regulator, Mallory 110 GPH Marine pump. Pressure stays at 6-7 PSI while the surge is happening.
    Last edited by Shaun; 07-13-2010 at 07:49 PM.

  7. #5
    Senior Member GT Jets's Avatar
    Join Date
    Jun 2008
    Location
    Morgan Hill
    Posts
    2,234

    Default

    Quote Originally Posted by Shaun View Post
    Mallory Regulator, Mallory 110 GPH Marine pump. Pressure stays at 6-7 PSI while the surge is happening.
    You can still have 7 PSI and be aerating the fuel, so may be a good idea to check for potential leaks at joints to be sure.

    As weird as this sounds, maybe extended jets in the rear bowl?

    If you back out ever so slightly, does it go away? I would love to see a spark plug or two after a hard surging run and a hard shutdown, that may tell a story....BTW, do you have a rev limiter? what pill? I have seen these do some moronic magic .....
    GT


    Quote Originally Posted by Quickjet View Post
    Put a 300 on the back of it, Flywheel it and a nosecone. $15,000 later you'll have a 65 mph pile of shit......

  8. #6
    I'm No Expert Shaun's Avatar
    Join Date
    Feb 2008
    Location
    San Clemente, Ca
    Posts
    3,138

    Default

    Well, the fuel rail and regulator are mounted to the manifold. Could vibration be aerating it that bad? And if so, why only when from a idle? I can stab the gas at 3K rpm and get no surge. I have never tired to back off the throttle a tiny bit during the surge. I do have a rev limiter (6AL box) with a 6400 RPM pill. The surge is happening around 5000 RPM.

    Rear bowl? These are mounted sideways

  9. #7
    Senior Member GT Jets's Avatar
    Join Date
    Jun 2008
    Location
    Morgan Hill
    Posts
    2,234

    Default

    Quote Originally Posted by Shaun View Post
    Well, the fuel rail and regulator are mounted to the manifold. Could vibration be aerating it that bad? And if so, why only when from a idle? I can stab the gas at 3K rpm and get no surge. I have never tired to back off the throttle a tiny bit during the surge. I do have a rev limiter (6AL box) with a 6400 RPM pill. The surge is happening around 5000 RPM.

    Rear bowl? These are mounted sideways
    Then "front jets" LOL could be starving the forward jets from the fuel level and sucking air....

    A good experiment would be to raise the floats 1 turn....That is if it does not flood...

    Not an expert, just play one on the forums....
    GT


    Quote Originally Posted by Quickjet View Post
    Put a 300 on the back of it, Flywheel it and a nosecone. $15,000 later you'll have a 65 mph pile of shit......

  10. #8
    cfm
    cfm is offline
    Banned
    Join Date
    Jan 2008
    Posts
    1,263

    Default

    Quote Originally Posted by GT Jets View Post
    You can still have 7 PSI and be aerating the fuel, .
    I had a dyno fuel flow meter that did that to me. Proof was me looking thru the glass sight bowls during many full throttle runs while the engine shaked/bucked going over 16:1 A/F ratio and me trying to cover my privates in case the engine would kabloom.

    Went thru this pulling/changing fuel system components one by one. Everything returned to normal when the meter was removed. Meter was on the pressure side.

    Fact, not theory.

  11. #9
    Senior Member GT Jets's Avatar
    Join Date
    Jun 2008
    Location
    Morgan Hill
    Posts
    2,234

    Default

    Quote Originally Posted by cfm View Post
    I had a dyno fuel flow meter that did that to me. Proof was me looking thru the glass sight bowls during many full throttle runs while the engine shaked/bucked going over 16:1 A/F ratio and me trying to cover my privates in case the engine would kabloom.

    Went thru this pulling/changing fuel system components one by one. Everything returned to normal when the meter was removed. Meter was on the pressure side.

    Fact, not theory.
    The number one reason I try to get at least a foot of fuel line after the regulator, unless it is a bypassing dealio..You can get "flash gas" to the carbs....
    GT


    Quote Originally Posted by Quickjet View Post
    Put a 300 on the back of it, Flywheel it and a nosecone. $15,000 later you'll have a 65 mph pile of shit......

  12. #10
    gn7
    gn7 is offline
    Senior Member gn7's Avatar
    Join Date
    Jan 2008
    Posts
    25,975

    Default

    What rail? Are you running one of those Mallory regulator logs. Does it surge until you let off or does it go away after time. When you punch it from a cruise, it never happens, no matter how long you stay in it. Maybe raise the fuel a tiny bit. All the bowls. If they have glasses, get it above half way. We are running the circle track floats with the carbs turned sideways. With the thin tapered side to the back. They helped.



    100% free webcam site! | Awesome chicks and it is absolutely free! | Watch free live sex cam - easy as 1-2-3
    Last edited by gn7; 07-13-2010 at 08:27 PM.

  13. #11
    I'm No Expert Shaun's Avatar
    Join Date
    Feb 2008
    Location
    San Clemente, Ca
    Posts
    3,138

    Default

    Bob, it's one of those from rex, nothing special. Suppose i should call it a fuel block and not a rail I'm going to check my float levels the next time i'm on the water. My old motor i had a issue at WOT where i was draining the rear bowls but it wouldnt happen until a few seconds into WOT. Also it felt totally different it wasnt a surge but was raspy sounding! One thing i noticed this trip out was that it also was doing it if i made a hard turn after i made a pass. I wonder if my foat levels are set too low.




  14. #12
    I'm No Expert Shaun's Avatar
    Join Date
    Feb 2008
    Location
    San Clemente, Ca
    Posts
    3,138

    Default

    Bob, also the surge eventually stops if i stay on the throttle.

  15. #13
    Senior Member GT Jets's Avatar
    Join Date
    Jun 2008
    Location
    Morgan Hill
    Posts
    2,234

    Default

    Quote Originally Posted by Shaun View Post
    Bob, it's one of those from rex, nothing special. Suppose i should call it a fuel block and not a rail I'm going to check my float levels the next time i'm on the water. My old motor i had a issue at WOT where i was draining the rear bowls but it wouldnt happen until a few seconds into WOT. Also it felt totally different it wasnt a surge but was raspy sounding! One thing i noticed this trip out was that it also was doing it if i made a hard turn after i made a pass. I wonder if my foat levels are set too low.



    Raise the float levels and move the regulator and you should be GTG..

    BTW, Dat purdy...
    GT


    Quote Originally Posted by Quickjet View Post
    Put a 300 on the back of it, Flywheel it and a nosecone. $15,000 later you'll have a 65 mph pile of shit......

  16. #14
    gn7
    gn7 is offline
    Senior Member gn7's Avatar
    Join Date
    Jan 2008
    Posts
    25,975

    Default

    Quote Originally Posted by GT Jets View Post

    BTW, Dat purdy...
    Yep! That was a worn out POS on the side of Dads garage. Shaun built two motors for that thing, over the internet. I can say one thing. He follows instructions well.


    Shaun, get over here and pick up my monitor. That last post knocked on the floor!



    100% free webcam site! | Awesome chicks and it is absolutely free! | Watch free live sex cam - easy as 1-2-3

+ Reply to Thread

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

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