Yamaha F20 Won't Start

I would see if you can try another tank, bulb and hose from someone else before you purchase all new stuff. It gets costly and unless its really in need of replacement you may be just wasting money away. Not too handy with the four strokes but guys like creek and cut runner are the ones who are the experts

 

First check to see if the fuel line is plugged in correctly. There is an arrow on the fuel bulb and a check valve in the tank fitting. Often the tank to fuel line connecter can be a little hard to get all the way in.

Frank_S

 

The 2nd time did you pull the carb bowl screw? If so did it fire up?

Pull the fuel line going into the carb from the fuel pump, try to prime the ball (Careful gas should squirt out of the disconnected line) if gas comes out then the problem is in the carb.

If no gas comes out then reconnect the line and pull the line going into the fuel pump, and repeat by trying to pump the ball. Keep working your way out until you find where no fuel comes out and that will be where I would start looking for a problem.

If I was to just make a guess right now with no additional diagnosis I would say you have a stuck needle not allowing the bowl to fill with gas.

 

When you say you removed the fuel line fitting, are you saying that you unhooked the fuel line from the engine (IE the quick disconnect).  Or are you saying you removed the fuel fitting(IE the quick disconnect) from the fuel hose?
If you did it the 1st way the primer bulb should be hard all the time, if you did it the 2nd way; you should be able to squeeze the bulb every time and gas should squirt out.

If you did remove the fitting from the line itself and gas would not squirt out when you primed the bulb replace your primer bulb and retest.

This is the same thing I suggested in my 1st post just starting from the opposite end.

1 Remove the fuel hose from the primer bulb on the engine side, ( so you should have the primer bulb connected to the gas tank but there shouldn't be any hose connected to the other end of the primer bulb, make sure you have the arrow on the primer bulb going the right way) Squeeze the primer bulb gas should squirt out, every time you squeeze the bulb. If no gas is present then get a new primer bulb and retest. If gas is present move forward to step 2.

2) Reconnect the fuel hose to the primer bulb and remove the quick disconnect fitting from the fuel line that attaches to the engine, squeeze the primer bulb gas should squirt out every time you squeeze the bulb. If gas is present then your problem is your quick connect replace and retest. If no gas is present go to step 3

3) Repeat the above step at every connection/part until you find where gas will not pump freely. Next part would be the quick disconnect on the engine itself, then the fuel filter, fuel pump, and then carb. If gas flows freely at every junction then you problem is in the carb.
This is a simple test that should take about 10 min.

Let me know how it works out or if I can help any more.