hi guys i bought a quad the other day that has a yamaha 100cc in it and is in pretty good condition. i have a problem with it cutting out, the quad cuts out when i try to rev it up. I also have changed the pipe from the fuel filter to the fuel pump( it is sea through and should it be completely full or should small drops of fuel come out of the fuel pump). Is there a problem with the carbi as that's what i think it is , thanks
Quad engine problem
- Thread starter IKE323
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FatCat
2 stroke Addict!
It should be full of fuel. Take the fuel pump apart and inspect it. Is the filter clear? Take it off and back flush it with carb cleaner. Make sure that's clear. Then pull the carb and clean it. Definately sounds fuel related. Before you take it apart try playing with the choke and see if it picks up.
Doc Sprocket
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What kind of fuel pump is it? Diaphragm/vacuum, electric, or mechanical? FC's right, the line should be full. If it's a vacuum pump, you may have a bad diaphragm, cracked vac line, or a vac leak.
FatCat
2 stroke Addict!
That's what I was thinking. I've seen diaphragms get stuck from old gas. Could just be stck and need cleaned and reassembled. If that's the case it probably needs the carb cleaned to.
Yeah the filter is clear, and where is the choke ( is it the throttle or on the fuel pump) , sorry I have no experience
It looks mechanical as there is now wires going to it.
FatCat
2 stroke Addict!
What kind of quad is it? I know yamaha but do you know what model? Year? 2 or 4 stroke? If the pump has 3 rubber lines going to it its a vacuum pump. Fuel line from tank. Fuel line to carb, and vacuum pulse line to operate the the diaphram to pump fuel. If you can do pics that would help. Choke Could be a lever on the carb, could be up by the handle bars. depends on the machine. It's a yamaha its something simple. We can get you going 
What kind of quad is it? I know yamaha but do you know what model? Year? 2 or 4 stroke? If the pump has 3 rubber lines going to it its a vacuum pump. Fuel line from tank. Fuel line to carb, and vacuum pulse line to operate the the diaphram to pump fuel. If you can do pics that would help. Choke Could be a lever on the carb, could be up by the handle bars. depends on the machine. It's a yamaha its something simple. We can get you going
Ok will upload just now, the model is dominator(not known at all) but the engine is a Yamaha 100cc and the fuel on and off switch has 3 pipes on it, heres the images
O and i forgot to tell you guys that when the engine is running it looks like fuel is leaking from the carbi(or that black box in photo 2), it leaks quite a bit so that may help
Doc Sprocket
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What are the fuel tap positions labelled as? Is there a "prime" position? I suspect it's a vac-driven unit.
Yes it has a prime position , it's fixed on the right of the quad
Doc Sprocket
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Yup. On those, fuel flows freely in the "prime" positioin but relies on engine vacuum in the "on" position. try leaving it in the "prime" position and see if it's any better...
Ok I'll figure out which is which. Must the fuel pipe from the filter to the carbs be full in the prime position when the quad is turned on?? Cos it's never full
Doc Sprocket
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I would think it should.
What kind of quad is it? I know yamaha but do you know what model? Year? 2 or 4 stroke? If the pump has 3 rubber lines going to it its a vacuum pump. Fuel line from tank. Fuel line to carb, and vacuum pulse line to operate the the diaphram to pump fuel. If you can do pics that would help. Choke Could be a lever on the carb, could be up by the handle bars. depends on the machine. It's a yamaha its something simple. We can get you going
i think i may have found a problem but not sure where this pipe has come from and cannot see any other places to fit it, could there perhaps be other factors that effect the quad ?
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