carb project

  A carb works by mixing fuel and air together for a internal combustion that takes place in the boar to pump the pistons. The carb works by sucking in air through the choke valve in to the Ventura which helps speed up the flow. Fuel is then added to the air by the jet, it sprays the fuel into the passing air which is then sucked trough the throttle end and flows into the boar via the valves.  The amount of air and fuel that goes into the boar is controlled by the throttle valve that opens and shuts according to how throttle you pull

difrent parts of a carb help with the process of mixing fuel and air for the combustion process. in the diagram beside it shows the flow of  clean air entering the carb via the choke plate or butterfly valve.the air is then sucked through a ventura  due to atmosperic pressure casue by the draw back off the piston.the fuel is sprayed out by a fuel jet, there are sevral types of jets eg a idle jet and running jet. the float chamber holds the fuel at atmospheric pressure ready forr mixing or use.the amount of fuel is controlled by the float driven valve wich is controlled by the float, the float drops as fuel leaves the float bowl wich opens the inlet valve for more fuel to be pumped in , the float rise up and shuts off the valve so the carb dose not flood.the oxogen and fuel mixture then travels through the carb to the throtle plate wich controlls how much of the mixture goes into the boar, the throtle valve is controlled by the throtle leaver on the boat  opening alowwing more mixture to go faster and shuting off to slow down reducing the amount of  fuel and air entering the boar.

an emulsion tube  has sevral small holes in wich it air is introduced to the mixture  to atomize and correct  excessive richness at high speeds. the emulsion tube also helps improve idle response and stability when the engin is hot and prevents fuel precolation and genral hot starting problems.

A manual choke is used manually and has to be shut off and put on by the operater. the manual choke closes the choke plate of butterfly valve alowing only a small amount of air into the carb for a more richer mixture to start a cold engin. A automatic choke is one that the engins computer can shut off and turn on by sensing the tempreture of the engine. The point in having a choke is so the car can start easyer  as it alos less air flow and more fuel to be pumped into the boar .a manual choke is located at the front of the carb and can be turned off and on from the car or a switch attached to the choke leaver.

a lift pump is used to raise the level of fluid such as gas or desil into the fuel ines (dose not force it thorugh)   the fuel lines  from the tank. it works by building pressure in the gas tank drawing fuel into the fuel lines .vacum fuel pumps for a two stroke work on a low presure system  drawing the fuel through the fuel lines. Average pressure created by these pumps is anywere between  3-5 psi.

the difrences between diesel and petrol?

diesel is more efficiant and powerfull than petrol due to the hydocarbons with long carbon chains. although diesel is more efficant it puts off alot of  polution and gasses than petrol.in most countries desil is cheaper to buy than petrol. both diesel and petrol are made from crude oil pumped from oil rigs. the hydrocarbons in petrol are alot lower than diesel making it more flamable than diesel. diesel has higher coefficient than petrol thus is why it is used in more heavyer vehicals for transportation.

a fuel shut off solenoid runs off electrical current.the fuel pumps through it at its average speed. the solenoid is desinged to pick up anything weird in the flow such as heat, if a thing like heat is picked up in the solenoid it is sent an eltrical current wich shuts the valve stopping fuel from going anyfurther into the engin.  A device like this is a must as it can prevent any further fuel being added to a fire or broken part on the boat if it is carshed or involved in a accident.

a four stroke sytem is  described in a 4 step plan, intake compression power and exhaust. the intake involves the mixture of air and fuel weather that be carb or injection, the inlet valve opens and lets in the mixture of air and fuel into the boar.  the compression part is when the piston pumps up compressing the mixture. power is when the spark plug ignites  the compressed mixture and forces the piston on its down stroke, exhaust is when the out let valve opens and the piston pumps up forcing the burnt mixture in to the exhaust pipe and out into the atmospher.

more to come.....