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Carb Hesitating


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I have a Carter 1 barrel carb that was hesitating when I pull out in first,and shift it into second. The quick fix was to close the choke half way and it would run really good. I'm going through the carb now (was sitting for 3 months in a ziploc bag,installed it on my engine and gas was pouring out from the base gasket)I want to know if I should drill one of the jets bigger to richen it up? Thanks, Greg

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No, drilling jets is really bad idea. When they are manufactured the dia is very close tolerance and just running any old drill through one will wreck it.  You are trying to compensate for a problem which is nothing to do with jet size. Obviously check that you have the correct main jet to start with, assuming you have then check for a blocked accelerator pump.  Its very easy to make sure it is working correctly remove the air filter look down the choke and work the  throttle open and closed as you do this you should see a visible squirt of fuel.   This 'extra shot' of fuel is what happens every time you accelerate away and change gear.

 

If it isn't working pull the top of the carb off and you will see the plunger and operating rod, open and close the throttle again and the pump should move up and down.  Assuming it is operating pull the pump out and you will see a small check ball held in by a circlip check that is all clear and so are the passages to and from it by blowing compressed air through. 

 

Having read your post again it could also be that the float is sticking, you shouldn't have fuel leaking out of the base gasket.  If the float is stuck open there is no control of fuel level which will spill through the carb and run down leak out.  The float level on the B&B single barrel DTE2 is 5/64 so check that and make sure the float operation is good.

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Gas running out can also mean it can suck air in, leaning out the mix, one of the reasons half choking makes it run better.  Check the base  with a straight edge for warpage.

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My reply to Jeff's hesistastion problem.

 

"When the gas pedal is pushed to the floor, you open the throttle plate to allow more vacum to pull gas through the different circuits.

The top plate is the choke, when warmed up it should be wide open, if not, find out why and fix it.(sometimes a short throttle cable can cause idle fluctuations with the engine moving in a different direction than the cab)

If it's a hard pedal push....the accelerator pump is allowed to shoot a steady stream of gas into the system.

When you floor it (WOT-wide open throttle)...the vacum drops to zero and needs to build up to continue sucking gas. To help during this vacum drop, some carbs have a power circuit, power system or power valve.The way most work is vacum keeps the circuit closed....when vacum drops...it opens up usally letting raw gas pour in til vacum rises to close it. The B&B has a Step-Up Jet that does this, sometimes called the Power Piston.

The idle mixture screw has to be set right, to get the other circuits to run right. If not, you have multiple WOT issues (meaning no fuel). "Set right" means getting the most vacum you can at idle.

 

Not sure you have a Carter B&B, but this is still a good read: 1948 Chrysler Reference Guide On The Story Of The Carburetor

 

And of course the youtube videos on rebuilding a B&B: Carter BB Carburetor Assembly Part 1 of 2   Carter BB Carburetor Assembly Part 2 of 2   "

Edited by 48dodger
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Thanks for the replies. When I first overhauled this carb back in august, it was running good and slowly the hesitation appeared. I never soaked the excelerator pump in oil. I think this might be the problem. The carb and the fuel pump was dry without fuel for three months while I overhauled the engine, and after installing it the fuel pump that I bought in August doesn't work, so I poured gas in the vent tube to fill the bowl so I could start the engine and it was leaking. Looks like from the spacer gaskets in between the body and the base plate. Got a new carb kit and fuel pump that's in the mail and will see how it turns out. The info from this site is priceless. Thanks, Greg

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Greg be very careful in matching up those spacer gaskets. There are some slight variants over the years. You can have gaskets that match the hole pattern but the inner hole size will be too big and not make a good seal.

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  • 1 year later...

I'm just adding to this thread as a way to say "Thank You" to the members who contribute and give ideas and suggestions on resolving issues that come up.

 

I was having a similar hesitation issue to 8Secondss that just suddenly happened yesterday morning. I limped the Cranbrook back home and then started by doing a search on the forum for hesitation and came across this thread.

 

In my case it was caused by the retaining spring that holds check ball underneath the Accelerator Pumps coming up and allowing that check ball to move around in there. But while I had it apart, I used Don's suggestion of immersing that Accelerator Pump in oil overnight. After putting the carb back together and back on the engine. It started up and I'm able to drive around town again.

 

For someone that hadn't touched an engine in near 40 years to actually be able to fix something is a big deal :D So again, thanks to all the experts who are so helpful.

 

Tony

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