# Yamaha F20 Won't Start



## Paul_Barnard (Oct 28, 2011)

I bought a second hand F20 a few months ago. It ran perfectly though it has always taken 6-7 pulls to get going. I have run Stabil Ethanol treatment through it since I got it Last week I went out to the driveway to run it because It had been nearly two weeks since I had started it. It would not start. Every 4th or 5th pull it would pop like it wanted to start, then nothing. I turned the carb drain screw and gas dripped out, so I knew it was getting fuel. After I did that it seemed more excited about starting, so I did it again after disconnecting the fuel hose. It finally started and ran flawlessly. I disconnected the fuel line and ran it dry.

Yesterday when I got back from vacation I reconnected the fuel line. The fuel bulb was HARD. I couldn't compress it at all. Needless to say, It wouldn't start. I don't think I have a bad gas problem, because it runs great when it starts. The vent on the tank is open. The fuel filter is clean. Where should I start troubleshooting. Replace the fuel bulb or line?


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## AfterHours2 (Aug 2, 2010)

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


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## Frank_Sebastian (Oct 15, 2007)

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


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## Paul_Barnard (Oct 28, 2011)

> 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


What you are saying seems to make sense. It is as if the fuel cannot flow from the line through the connection on the engine. I did double check. It snaps snugly into place.


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## Creek Runner (Sep 1, 2011)

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.


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## Paul_Barnard (Oct 28, 2011)

I did not loosen the drain screw a second time. I removed the fuel line fitting (the one that connects to the engine) from the fuel line.  I squeezed the bulb a few times.  It pushed a little gas out initially, then no more even after I squeezed the bulb another 20 or so times.  I should be pumping gas out with every squeeze of the bulb huh?  

That still doesn't explain why the bulb was hard after I disconnected the line, ran the engine dry, then reconnected it.  It would seem at that point that I could compress the bulb some.

The gas tank is brand new.


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## Creek Runner (Sep 1, 2011)

> I did not loosen the drain screw a second time.  *I removed the fuel line fitting (the one that connects to the engine) from the fuel line. * I squeezed the bulb a few times.  It pushed a little gas out initially, then no more even after I squeezed the bulb another 20 or so times.  I should be pumping gas out with every squeeze of the bulb huh?
> 
> That still doesn't explain why the bulb was hard after I disconnected the line, ran the engine dry, then reconnected it.  It would seem at that point that I could compress the bulb some.
> 
> The gas tank is brand new.


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.


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## Paul_Barnard (Oct 28, 2011)

Thanks CreekRunner. I replaced the fuel hose, primer bulb and fittings. She runs like a champ. I probably could have isolated the individual bad part, but I thought what the heck, I'll just do it all.


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