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L20B Carb problems


Andres131313

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Turn the auto correct off. Spelled wrong is better than the wrong word.

 

The fuel is sucked into the carb by the in rushing air. Likely the primary jet is clogged with sediment. Time to rebuild it or at least take apart and clean it out. Check a few things. When done replace the fuel filter to prevent this. Cut the old filter open and have a look at the contents.

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A carb is just like a toilet. The fuel pump pressure just fills the bowl until the float rises and closes the valve. Fuel pump pressure wont make anything go down the intake. If it does, you have a float valve (needle and seat) problem.

Air is pulled through the throat of the carb, from the intake stroke of the piston,  It creates a syphon or vacuum, that pulls the fuel from the bowl through  tiny orifices called jets. when these jets get plugged with whatever, nothing gets through. This wont effect the acc pump. If it isn't working, that is a seperate problem.

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cycle the linkage so you see gas in the accell pump squirting. If not squirting then the float bowl is empty or the accell pump not working.

If bowl empty then the needle valve is not letting gas in or your your fuel pump is not working.

accel pump maybe you put the diaphram in backwards if that is possible.

 

when you dump gas in your carb your bypassing everything

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The accel pump linkage to the throttle is too long. It keeps the pump mostly down and it won't go high enough to pull in fuel. I know it works because I when I pull the linkage off and move the arm by hand it works. I had clean it all out. I'll try when I get home girm my robotics competition. I need a new throttle cable mount. Anyone know where I can get one or make one?

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take photos of this crap so we get a idea.

 

acell pump work or it dont. think of it as a soda at Mc Donalds. you have a straw in there. you sqeeze your cup the soda comes out threw the top of the straw. Thats it. same priceipal. No work means diapram cracked ,backwards or no gas in fuel bowl.

 

No gas in fuel bowl is needle valve stuck. float stuck at top. bad fuel pump. or crank fuel line before fuel pump (mechanical)

 

 

buy a new weber DGV. I cant even work on a stock carb

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I don't have that option right now. I took the air cleaner off and put some gas down the car to just get it started. As soon as it started I oppened the throttle wide open. I saw that the gas was finally goin in so I slowly backed off and it stopped pulling it in before it got lower then 3000 or so rpm. I know I got close to redline. What does this mean?

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I don't have that option right now. I took the air cleaner off and put some gas down the car to just get it started. As soon as it started I oppened the throttle wide open. I saw that the gas was finally goin in so I slowly backed off and it stopped pulling it in before it got lower then 3000 or so rpm. I know I got close to redline. What does this mean?

Is the anti dieseling solenoid working? It should "click" when energized (key on).......also, don't get so close to redline lol.

Sounds to me like the slow speed circuit in the carb is plugged/non flowing. Check that solenoid though first, it will cause issues like you are describing.

--Ray

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So I rebiult my engine and I'm having problems with my carb. The jets won't spray gas. It will only run when I pour gas in the carb. There is fuel in the carb but it won't go through the jets. Like there's no fuel pressure. What's up with it?

 

 

The accel pump linkage to the throttle is too long. It keeps the pump mostly down and it won't go high enough to pull in fuel. I know it works because I when I pull the linkage off and move the arm by hand it works. I had clean it all out. I'll try when I get home girm my robotics competition. I need a new throttle cable mount. Anyone know where I can get one or make one?

 

 

I don't have that option right now. I took the air cleaner off and put some gas down the car to just get it started. As soon as it started I oppened the throttle wide open. I saw that the gas was finally goin in so I slowly backed off and it stopped pulling it in before it got lower then 3000 or so rpm. I know I got close to redline. What does this mean?

 

This person does not have much experience with carbs of any kind, you would just trade for a bunch of new questions. There is nothing wrong with the stock carb when new. Comparing to a brand new weber isn't really fair. That said perhaps a new carb might be the ticket but for now this is what we are working with and it should be explored fully to get it running.

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I found a webber 32/36 for 70.00 ... there out there on the web you just have to look... the worst thing I ever did was put money into a stock Hitachi carburetor they are the worst pieces of crap ever invented...

 

Absolutely they, (the Hitachi) are problematic when worn out or not maintained. A $70 weber is just someone else's problem sold to someone else. They are invariably 20-30 years old, have been rebuilt 4 -6 times and have parts missing. They may or may not come with the correct adapter plate, gaskets or the proper air filter. If suggesting a weber, suggest a new one for just under $300. All these parts are included and best of all it's new.

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 I saw that the gas was finally goin in so I slowly backed off and it stopped pulling it in before it got lower then 3000 or so rpm. I know I got close to redline. What does this mean?

 

You aren't going to see fuel going down the throat of the car when it on the idle circuit. That happens bellow the butterfly.  Stupid question, where is the air fuel screw set at? 

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we all had to learn the hard wayWebers are the way to go

But I did fix a 521 stock hitachi . the mixture screw setting was off and carb was loose on the manifold.

 

I got truck to run will the accell pump. then got up the revs and blocked the main barrel side with my hand and open the 2nd to keep it running.

that's how figure it was the main side bad. think it ran on main side also but got fixed.

 

stock hitachi once worn take to the dump is my old mans advice or don't buy old cars.

 

As for shipping the carb FREE H@) Doctor that people don't appreciate this in the end and the car will get scrapped about a month after you give the part. Unless his a good frinds that will actually be into Datsun for over 10years.. Thses are the people I give parts to and then expect the same if I need a part from them

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