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Does a carburettor engine apply fuel at high speeds when the pedal is no longer depressed?

At a base level, carburetors meter the amount of fuel they let into the engine by the amount of air that is moving through them. Vacuum is created by the piston moving in the engine and creating an ...
Justin Lloyd's user avatar
15 votes

Does a carburettor engine apply fuel at high speeds when the pedal is no longer depressed?

Carburettors are very crude in comparison to EFI systems, and so the amount of fuel entering the engine is simply a factor of the amount of air going in, which is controlled by the position of the ...
Nick C's user avatar
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10 votes

Does a carburettor engine apply fuel at high speeds when the pedal is no longer depressed?

Carburetor Circuits Will Still Pull Fuel from the System If the engine is running on a carbureted vehicle, off throttle or not, it will consume fuel. Throttle Settings There are three basic ...
DucatiKiller's user avatar
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8 votes
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Basic operation of a choke valve

You should avoid over-use of the choke if possible, as over-fuelling the engine will cause more carbon build up, shortening the life of the plugs and reducing the time before the engine needs a "...
Nick C's user avatar
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7 votes
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Carb. Rebuild or Adjustment?

I'm not a watercraft Mikuni guy, but I've dealt with a few two-stroke carbs that work in this manner. There's a few possibilities: The internal filter screen is clogged, but I'm discounting this as ...
SteveRacer's user avatar
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6 votes
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How to troubleshoot carburetor?

These symptoms are typically caused by one or more blocked jets in the carburettor. Small particles of grit can block any one of the jets in carburettors. The fuel still gets to the engine through ...
Chenmunka's user avatar
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6 votes
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Yamaha Seca - Motorcycle Idle problems

More than likely, you have an air leak If you haven't cleaned out and rebuilt a bunch of 4 carburetor banks in your life there is a good chance you have accidentally created an air leak in the system....
DucatiKiller's user avatar
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6 votes

Can't start a Kawasaki GPX 750

Your carbs are clogged with varnish and bad gas The remnants of gas that has evaporated are a gummy hard varnish inside of your carburetors. You have a bit of work to do. You need to completely ...
DucatiKiller's user avatar
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5 votes
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Motorcycle bogs down under load

You are describing a lean condition The more you open your throttle the more vacuum you are creating in your carburetor venturi and your intake manifold. When you are operating at higher RPM any ...
DucatiKiller's user avatar
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5 votes

Can't start a Kawasaki GPX 750

It sounds like your carb(s) are plugged and need cleaned. If the fuel in the carbs has ethanol in it, the carbs are going to be caked with crap. The floats could be ruined. There are a lot of things ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
5 votes
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What is the yellow precipitate in my outboard's carburetor?

Those are the remnants of gasoline When you let gasoline evaporate it leaves behind various elements within the gas that can't dissipate through evaporation. These remnants can clog various galley'...
DucatiKiller's user avatar
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5 votes
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Adjust carburettor without hi-speed adjustment

Yes, you can bend the tab The metering diaphragm enriches the entire range on every circuit. If the fuel level is higher it will require less vacuum under Venturi's Law to pull the fuel from the '...
DucatiKiller's user avatar
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5 votes
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Properly draining a motorcycle carburetor

A few minutes of fuel leaking is more than you should expect. Usually, when you drain a carburettor, if the fuel lines are full as well as the carburettor, I expect about 10-15 seconds maximum. If ...
anonymous2's user avatar
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5 votes
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07 Suzuki Boulevard S40 leaking gas

Sounds like the carburetor, float, and/or float valve may be dirty. NOTE: A service manual will be extremely helpful as you go thru this process. There is no reason to take this carburetor apart ...
CharlieRB's user avatar
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5 votes
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What is this tube coming off from 1 of 2 motorcycle carburettors?

Well... Mr google said: The OEM petcock is vacuum actuated. With a properly operating petcock, unless the engine is producing vacuum the petcock will not flow gasoline while in the ON or RES ...
SteveRacer's user avatar
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5 votes
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Purge carburetors on Yamaha XJ 600

I finally got the motorbike to start! As suggested by @Pᴀᴜʟsᴛᴇʀ2 in question comments, I purged both the carbs and the tank. The picture is not that great, but the fuel in the right jar on the last ...
Jérôme's user avatar
  • 201
4 votes

Basic operation of a choke valve

What is the optimal use of a choke? Knowing how to use it as explained by Nic C What are the cons of using it incorrecly? Fouling spark plugs which will cause a misfire even after it warms up. ...
Moab's user avatar
  • 7,990
4 votes

Dirt bike carburetor problems

Replace the float as well. Sometimes depending upon what material it's made the float can be somewhat soaked with fuel changing the weight of it.
Rodrigo Alencar's user avatar
4 votes

How to troubleshoot carburetor?

There are quite a few things that can effect your bike in this way First, you need to truly identify the issue. Before you tear down your carburetor you may want to engage in some troubleshooting ...
DucatiKiller's user avatar
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4 votes

Hero Passion Pro - Choke Issues

I assume you mean that when the engine is cold, it requires the choke, but then if you stop and try to restart, then you have to turn off the choke. This is by design. The choke is a tool to allow a ...
Rory Alsop's user avatar
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4 votes
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What fuel lines are recommended for a propane carburetor?

In Australia, our Automotive LPG hose standard is: • AS/NZS 1869 class D According to the following document, it appears that in the US propane hoses for automotive use needs to meet: • NFPA 58, ...
Aaron Lavers's user avatar
  • 1,596
4 votes
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Float carburetor leaking gas

More than likely the float is saturated or non-existent, allowing the bowl to be over filled constantly (not stopping the flow of fuel into the carb). It could also be the needle valve not seating ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
4 votes

Why 3 x 2 barrel carbs on a v8 does not 4 x 2 make more sense with one two barrel per two cylinders

A 3x2 setup tends to run on just the middle carb most of the time and the throttle on the outer two is only opened in high rpm operation. There isn't a need to match the number of barrels to the ...
Dave Smith's user avatar
4 votes
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Is my mixture too rich?

The fotos differ each in color. Try to capture the plug in natural light, without flash. Unless the colors in the foto are totally wrong, there can't be much wrong with the engine. Seems to be a nice ...
Martin's user avatar
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4 votes
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If I start a previously unfueled small engine, do I keep choke on for first pull only or until it starts?

I think you're overthinking it a bit. Just follow the directions. As far as fuel in the float bowl, if the fuel tank is above the carb (which I believe is the case ... especially if it doesn't have a ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
3 votes
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Reconnecting Kawasaki GPX 750 1998 to Keihin G301 carburator

Here are the various connections based upon your images. I have left the label spelling in the image provided the same as the image. They match any misspellings in the three images. Image 1 "I don'...
DucatiKiller's user avatar
  • 32.9k
3 votes

Dirt bike carburetor problems

Needle and seat issue Your needle isn't hitting the seat in the float. check for physical obstruction of the floats always replace the needle and seat as a pair. They fit together. ensure your ...
DucatiKiller's user avatar
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3 votes

Percent of Air and Fuel used for Combustion

Upto to which point this air can be reduced. (I mean in the AFR ratio like 10: 1 , 8: 1) ? Realize, if you were to open the butterflies and nothing else were to occur (no additional fuel), you'd ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
3 votes

Percent of Air and Fuel used for Combustion

Let me see if I can clear some of this up for you. The stoichiometric ratio (AFR) for the petrol is 14.7 : 1 right? This is correct, and it's important to understand the concept of stoichiometric ...
JPhi1618's user avatar
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3 votes

2002 Suzuki RM250 - Dies after warm up, restarts after cleaning wet plug

Here's a theory Too much fuel built up in the crankcase. Could be from a petcock leaking and a stuck float. Here's the theory Too much fuel in the crankcase. You start the bike. It begins to ...
DucatiKiller's user avatar
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