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Anyone have any additional info to help me out on this project?
I am in the process of trying to get a pair of 1994 L250TXRS’s running. These engines have been sitting for over four years. They were running when parked but are no starts now. I have replaced six fuel pumps, using an external pump, recirculated fresh gas through entire system by removing inlet to each carb and attaching a return line to recirc tank, fuel lines look good, sprayed oil into each cylinder, rotated by hand they turn nice and smooth, new plugs and filters ready to install. Removing and cleaning all twelve carburetors is going to be my next step.
Not being familiar with the system I had a couple of questions. Also a PDF file on the electrical will most likely come in handy.
1. Does the electric fuel pump run continuously when the key is on?
2. Is the electric pump a diaphragm or centrifugal pump?
3. What pressure does the fuel pressure regulator maintain on the system?
4. What actuates the fuel solenoids (12 volts?) and when are they activated?
Any other advice you might have to offer will be highly appreciated.
Thanks, Yarb
Re: L250TXRS fuel system help needed
Let's start with some easy stuff first.
The diagram below shows the solenoids for each carburetor.
The engine CDI tells the solenoids when to open and for how long.
It is presumed that the pump must run continuously so any time that a solenoid needs to be activated that fuel pressure will be available at the solenoid.
It appears that the pressure regulator outputs a pressure of 1.4 psi.
Here is some descriptive text from a Yamaha book about the system on your motors.:
Electronic Carburetion System (ECS)
The ECS assists in delivering some of the required fuel to the intake tract of each of the six carburetors without using the normal carburetor circuits. Fuel for the ECS is drawn from the #6 carburetor float bowl. Any problem in the fuel supply to the #6 carburetor can affect the ECS operation.
Inside the YMIS (Yamaha Microcomputer Ignition System), a computer program signals when the ECS solenoid valve on each carburetor should open to add fuel. The ECS is designed to supplement the carburetor fuel delivery under the following conditions:
1. Cold starting
2. Warm-up
3. Rapid acceleration
4. Detonation
5. Rapid deceleration
I am in the process of trying to get a pair of 1994 L250TXRS’s running. These engines have been sitting for over four years. They were running when parked but are no starts now. I have replaced six fuel pumps, using an external pump, recirculated fresh gas through entire system by removing inlet to each carb and attaching a return line to recirc tank, fuel lines look good, sprayed oil into each cylinder, rotated by hand they turn nice and smooth, new plugs and filters ready to install. Removing and cleaning all twelve carburetors is going to be my next step.
Not being familiar with the system I had a couple of questions. Also a PDF file on the electrical will most likely come in handy.
1. Does the electric fuel pump run continuously when the key is on?
2. Is the electric pump a diaphragm or centrifugal pump?
3. What pressure does the fuel pressure regulator maintain on the system?
4. What actuates the fuel solenoids (12 volts?) and when are they activated?
Any other advice you might have to offer will be highly appreciated.
Thanks, Yarb
Re: L250TXRS fuel system help needed
Let's start with some easy stuff first.
The diagram below shows the solenoids for each carburetor.
The engine CDI tells the solenoids when to open and for how long.
It is presumed that the pump must run continuously so any time that a solenoid needs to be activated that fuel pressure will be available at the solenoid.
It appears that the pressure regulator outputs a pressure of 1.4 psi.
Here is some descriptive text from a Yamaha book about the system on your motors.:
Electronic Carburetion System (ECS)
The ECS assists in delivering some of the required fuel to the intake tract of each of the six carburetors without using the normal carburetor circuits. Fuel for the ECS is drawn from the #6 carburetor float bowl. Any problem in the fuel supply to the #6 carburetor can affect the ECS operation.
Inside the YMIS (Yamaha Microcomputer Ignition System), a computer program signals when the ECS solenoid valve on each carburetor should open to add fuel. The ECS is designed to supplement the carburetor fuel delivery under the following conditions:
1. Cold starting
2. Warm-up
3. Rapid acceleration
4. Detonation
5. Rapid deceleration
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