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another carb question
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DRR Sportsman
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I have a 1050 dominator that runs great but once I let off after the pass it wants to just die out is this a lean idle issue. thinking richen up the idle circuit some may help any thoughts?
 
Posts: 405 | Location: Bellingham MA | Registered: October 21, 2004Reply With QuoteReport This Post
DRR Top Comp
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Carb look like this? Except what?

 
Posts: 9398 | Location: Madeira Beach Fl. | Registered: June 12, 2018Reply With QuoteReport This Post
DRR Pro
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Mike do you have those lttle slosh tubes on the jets? Is the transfer slot square? If you keep listening to my expert advance sooner or later I will get one right
 
Posts: 1921 | Location: in a van down buy the river | Registered: September 07, 2002Reply With QuoteReport This Post
DRR Top Comp
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I do not think it is a lean idle issue. The hose on top in the picture above is good to have and may resolve part of the issue. Is it doing it when you let off on the gas or when you hit brakes hard? (could be sloshing fuel from vent tubes)

First I would start by doing what everyone needs to be doing to carb every other race or so. Blow out all of the bleed jets on top of carb with carb cleaner until you can see or hear that they are open. A carb will act goofy if they are clogged and they get clogged easily.

If it runs good until you let off then you may have a fuel supply issue. If you have a deadhead regulator remove it and throw it away or give it to someone you really do not like. You could make a pass and kill ignition and fuel pump immediately and then check float level and see where it is at.
Gas or Alcohol? Makes a difference on how we troubleshoot it.
If it is alcohol what needle and seats?
What fuel pump?
What fuel pressure?

With the limited information you gave us hard to diagnose but I would start with fuel sloshing if it is doing it under hard braking or float level when it does it.


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"Dunning-Kruger Effect"
-a type of Cognitive bias where people with little expertise or ability assume they have superior expertise or ability. This overestimation occurs as a result of the fact that they do not have enough knowledge to know they don't have enough knowledge.

Before you argue with someone ask yourself, "Is this person mentally mature enough to grasp the concept of a different perspective?" If not there is no point to argue.

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Posts: 3953 | Location: United States of Texas | Registered: April 02, 2011Reply With QuoteReport This Post
DRR Pro
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Did it just start doing it or has it always done it since you put it on?



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Posts: 2905 | Location: KIEFER, OK. | Registered: August 17, 2007Reply With QuoteReport This Post
DRR S/Pro
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quote:
Originally posted by camaro77:
I have a 1050 dominator that runs great but once I let off after the pass it wants to just die out is this a lean idle issue. thinking richen up the idle circuit some may help any thoughts?


Likely it's too rich from fuel slosh due to braking,,, easy to tell if this is the case, when you lift early in a run and don't brake hard and it doesn't do it... Adding extensions to the vent tubes is NOT the fix as fuel is not coming out of the bowl vents. Hard braking forces fuel from the primary side to ram into the jets and cause excess fuel to flow out the boosters. Another tell tail is if you pop it in neutral and give it throttle to keep it from stalling.

It this is the case your float level could be on the high side.
 
Posts: 2139 | Location: Tewksbury, MA,USA | Registered: November 03, 2000Reply With QuoteReport This Post
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quote:
Originally posted by TOP38:
quote:
Originally posted by camaro77:
I have a 1050 dominator that runs great but once I let off after the pass it wants to just die out is this a lean idle issue. thinking richen up the idle circuit some may help any thoughts?


Likely it's too rich from fuel slosh due to braking,,, easy to tell if this is the case, when you lift early in a run and don't brake hard and it doesn't do it... Adding extensions to the vent tubes is NOT the fix as fuel is not coming out of the bowl vents. Hard braking forces fuel from the primary side to ram into the jets and cause excess fuel to flow out the boosters. Another tell tail is if you pop it in neutral and give it throttle to keep it from stalling.

It this is the case your float level could be on the high side.


That was my thoughts and that is why I asked a few questions to narrow it down more.

A simple thing is to just change carb with another known good one to make sure it is in carb before going too far. If it does it with different carb look at fuel supply. If it cures it then possibly the whistle? inside has been removed, float level too high, fuel pressure too high. Just need more information, carbs are really simple overall.


https://postimg.cc/gallery/np3zpruo/
"Dunning-Kruger Effect"
-a type of Cognitive bias where people with little expertise or ability assume they have superior expertise or ability. This overestimation occurs as a result of the fact that they do not have enough knowledge to know they don't have enough knowledge.

Before you argue with someone ask yourself, "Is this person mentally mature enough to grasp the concept of a different perspective?" If not there is no point to argue.

4X NE2 CHAMPION. 2020 TDRA NE2 Champion
 
Posts: 3953 | Location: United States of Texas | Registered: April 02, 2011Reply With QuoteReport This Post



DRR Pro
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One or both idle stops are too high, you're pulling fuel through the intermediate circuit.
Put it in neutral as mentioned and see if that cleans it up some.


"Despite the high cost of living, it remains popular."
Dave Cook
N375
 
Posts: 1584 | Location: Indy | Registered: November 21, 2008Reply With QuoteReport This Post
DRR Sportsman
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quote:
Originally posted by Mike Rietow:
Carb look like this? Except what?


yes I have the hose
 
Posts: 405 | Location: Bellingham MA | Registered: October 21, 2004Reply With QuoteReport This Post
DRR Sportsman
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quote:
Originally posted by Curly1:
I do not think it is a lean idle issue. The hose on top in the picture above is good to have and may resolve part of the issue. Is it doing it when you let off on the gas or when you hit brakes hard? (could be sloshing fuel from vent tubes)

First I would start by doing what everyone needs to be doing to carb every other race or so. Blow out all of the bleed jets on top of carb with carb cleaner until you can see or hear that they are open. A carb will act goofy if they are clogged and they get clogged easily.

If it runs good until you let off then you may have a fuel supply issue. If you have a deadhead regulator remove it and throw it away or give it to someone you really do not like. You could make a pass and kill ignition and fuel pump immediately and then check float level and see where it is at.
Gas or Alcohol? Makes a difference on how we troubleshoot it.
If it is alcohol what needle and seats?
What fuel pump?
What fuel pressure?

With the limited information you gave us hard to diagnose but I would start with fuel sloshing if it is doing it under hard braking or float level when it does it.


carb is clean
fuel pump is magna fuel 500 set at 18 lbs
regulated to 6lbs at carb
running on gas
has done it all last yr but i just delt with it
I do get on the brakes pretty hard
I do shut it down and its a real bear to get restarted on the return road which I guess could be a rich condition
 
Posts: 405 | Location: Bellingham MA | Registered: October 21, 2004Reply With QuoteReport This Post
DRR Top Comp
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Are you sure the floats are good? When you have a bad float you adjust your needle and seat to get float level back up but it limits how much the needle opens.

I have never done this before but I think I would kill the motor and fuel pump as soon as you cross the line then check float levels. If it is low look for possible bad floats. I would also take float bowls off and flip them over and see where the floats are set. It probably should be around 3/8 inch gap at top upside down. If it is down much more than that bad float.

Do you know what needles and seats you have in there?

Your fuel pump and fuel pressure sounds good but that does not mean it is getting past the needle and seats. Do you know if that carb has the white plastic slosh whistles inside?

Those are a few things to check. Also I would change out carb with a known good carb to try just make sure it is carb. Although unlikely I have seen weird electrical problem with broken wire or bad connection under acceleration or stopping.
I really think it is a carb issue but since it is so easy to change it out I would try another just to make sure. Hope this helps narrow it down.


https://postimg.cc/gallery/np3zpruo/
"Dunning-Kruger Effect"
-a type of Cognitive bias where people with little expertise or ability assume they have superior expertise or ability. This overestimation occurs as a result of the fact that they do not have enough knowledge to know they don't have enough knowledge.

Before you argue with someone ask yourself, "Is this person mentally mature enough to grasp the concept of a different perspective?" If not there is no point to argue.

4X NE2 CHAMPION. 2020 TDRA NE2 Champion
 
Posts: 3953 | Location: United States of Texas | Registered: April 02, 2011Reply With QuoteReport This Post
DRR Pro
Picture of CURTIS REED
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quote:
Originally posted by camaro77:

carb is clean
fuel pump is magna fuel 500 set at 18 lbs
regulated to 6lbs at carb
running on gas
has done it all last yr but i just delt with it
I do get on the brakes pretty hard
I do shut it down and its a real bear to get restarted on the return road which I guess could be a rich condition


It's quite possible that if you are high on float level when you slam the throttle shut they are getting a large shot of fuel then trying to shut and do their job. Also with high float levels you get fuel slosh making it go way rich from both. I'm not talking about fuel out of the vents. JMO



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Posts: 2905 | Location: KIEFER, OK. | Registered: August 17, 2007Reply With QuoteReport This Post
DRR Sportsman
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I have a brand new TMC twin blade I will be trying hopefully soon
 
Posts: 405 | Location: Bellingham MA | Registered: October 21, 2004Reply With QuoteReport This Post
DRR Sportsman
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One question no one has touched on yet. I ask based on the answer that you gave saying this has been an issue for a while now. Where is the fuel cell mounted,and how high is it in relation to the carburetor? I ask based on a problem I had and was finally able to solve on my old car.
 
Posts: 484 | Location: Going to or returning from the chipmine. | Registered: July 01, 2011Reply With QuoteReport This Post



DRR Sportsman
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front mounted cell tube chassis car and its mounted to the main frame rails
 
Posts: 405 | Location: Bellingham MA | Registered: October 21, 2004Reply With QuoteReport This Post
DRR Sportsman
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Is the cell in the front or the back. If in back how high is the bottom of the cell in relation to the carburetor? Is it near the same height? Is the top of the cell above the carburetor? I’m looking for where the fuel level in relation to the carburetor
 
Posts: 484 | Location: Going to or returning from the chipmine. | Registered: July 01, 2011Reply With QuoteReport This Post
DRR Sportsman
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quote:
Originally posted by Wooley:
Is the cell in the front or the back. If in back how high is the bottom of the cell in relation to the carburetor? Is it near the same height? Is the top of the cell above the carburetor? I’m looking for where the fuel level is in relation to the carburetor
 
Posts: 484 | Location: Going to or returning from the chipmine. | Registered: July 01, 2011Reply With QuoteReport This Post
DRR Sportsman
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Sorry for double post.
 
Posts: 484 | Location: Going to or returning from the chipmine. | Registered: July 01, 2011Reply With QuoteReport This Post
DRR Pro
Picture of rusty
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quote:
One or both idle stops are too high, you're pulling fuel through the intermediate circuit.
Put it in neutral as mentioned and see if that cleans it up some.

x2,close the butterflies and open them equally,adjust fuel ratio for idle speed,or possibily a hole in the blade for air


honesty is the best policy,insanity is a better deffense
1.036, 6.16@ 224

 
Posts: 1389 | Location: texas | Registered: February 17, 2006Reply With QuoteReport This Post
DRR Pro
Picture of rusty
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if the carb has the baffle in the bowl that tube is not neede


honesty is the best policy,insanity is a better deffense
1.036, 6.16@ 224

 
Posts: 1389 | Location: texas | Registered: February 17, 2006Reply With QuoteReport This Post
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