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Ask Noel Schembri Your Own Question
Noel Schembri
Noel Schembri, Marine Technician
Category: Boat
Satisfied Customers: 1951
Experience:  Advanced technical diploma
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I have gas coming out of my Yamaha f150 vst. Its comminh out

Customer Question

I have gas coming out of my Yamaha f150 vst. Its comminh out of the emissions tubes. Which are for air. Seems the float isn't closing the gas line off. But I took the vst off turned it upside down and it all seemed to be working. Hooke's it back up same problem
Submitted: 2 years ago.
Category: Boat
Expert:  Noel Schembri replied 2 years ago.
Hello and welcome to Just Answer. If the float is moving what i am thinking is that the need is not closing. Try removing the VST and connect a fuel hose to it and using a primer bulb keep on pumping until the float is up and the bulb should harden and fuel stop. If it continues to flow then the needle would need to be replaced. Noel
Customer: replied 2 years ago.
When I do that test I cover the gas out tube with my finger right to simulate the engine not requiring more gas if so thenYeah i did that and the bulb hardened and gas stopped leaking . so I thought OK no problem. It must have been stuck but simply me removing it has freed it up. Though once I put it back in the engine and ran it . more gas out of the emissions. True said I did not open the vst and clean it but as it appeared to work I thought i would get away with it.Thabks
Customer: replied 2 years ago.
Could it be somthing to do with the cooling circuit or pressure regulator? Or they separate.Have I just been unlucky and its jammed up again immediate?
Expert:  Noel Schembri replied 2 years ago.
Inside the VST there is no high pressure as the pressure is created after it, so my guess is that the needle got stuck again. Try cleaning the VST carefully first and see it it will happen again, if no then you may need to replace the float or the seating. Noel
Customer: replied 2 years ago.
Okay thank I will do this today and get back to you. Its what I should have done.
Now I have to dig it out from behind the manifold again aaaaahhhhhh. Yamaha
Expert:  Noel Schembri replied 2 years ago.
Ok let me know how it goes Noel
Expert:  Noel Schembri replied 2 years ago.
Any good news?
Noel
Customer: replied 2 years ago.
Took vst off. Open it. And test the top half.
First test turned it upside down and blew into gas in tube. No go. Cleaned it all anyway. Seat and orifice. Put the top half of vst in bucket. Then hooked primer pump to gas in and started pumping. When the gas got to the to line where the bottom and the top half of the vst connect the float when up and the pump got hard and no more gas went in. Stuck it back on the engine and it still leaking gas.
Sure ly its a closed circuit . seems bizarre.
I just don't get it. Its so annoying taking it apart and back to find out I'm still at the same point. Is there anything else it could be. Have I hooked somthing up wrong. Going to check the manual today but I don't think I could have done that
Customer: replied 2 years ago.
The seat on the closing pin dies not look worn and its all working when in a bucket
Expert:  Noel Schembri replied 2 years ago.
Can you take a photo from where it is leaking? Noel

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