Help on 2000 Suzuki DT140 EFI - gas coming out of Throttle body

[texastraveler]

Help! I inherited this motor and never looked under the cowl while it was running until it started to run rough last weekend.. Starting it cold, it starts fine, but after a few seconds of running, Gas begins to pour out the throttlebody and causes the motor to run rough - obviously its getting to much gas. But why all of a sudden does it seem to start pumping extra gas into the throttlebody through a small hole close to the outer edge of the air intake. At first I thought it was the oil injection hole, but it turns out it is pure gas coing out of the hole. Is this a malfunctioning Choke? What do I need to check, or replace? Any Ideas?

 

[rodbolt]

Re: Help on 2000 Suzuki DT140 EFI - gas coming out of Throttle body

wasnt aware they made the DT140 in EFI. the DF140 was a 4 stroke EFI.
if its the 4 stroke EFI then check the needle valve assy in the VST. if its bad or dirty it will allow the VST to vent raw fuel into the intake manifold and then it will run out of the throttle body assy.
does the same on 2 stroke EFI as well.

 

[Dan366]

Re: Help on 2000 Suzuki DT140 EFI - gas coming out of Throttle body

I just had the same thing happen on a 115 Yamaha.

On the Yamaha, the low pressure fuel pump sends gas to a vapor separation tank. This tank has a float and valve needle just like a carburetor. If the needle isn't closing, the tank fills up, and vents into the "air intake" assembly.

On the Yamaha, getting to the vapor separation tank (VST) requires removing the intake manifold. I was able to fix it in an afternoon.

Dan

 

[texastraveler]

Re: Help on 2000 Suzuki DT140 EFI - gas coming out of Throttle body

Thanks for the info guys, The boat is 100 miles away at our lake property, so I won't have a chance to check out your suggestions until I can get back up there. I'll let you know what I find when I get back to it. Also, I might be off on the year of the motor, but I do know for sure that it is a 140hp 2 stroke with EFI, It has an oil injection tank, it has no Carbs, just one of what I have always referred to as a "throttle body". Thanks again, Ed

 

[rodbolt]

Re: Help on 2000 Suzuki DT140 EFI - gas coming out of Throttle body

doesnt matter, 2 or 4 stroke if its EFI it will have a VST,Vapor Seperator Tank.
all the VST is is a small tank that the high pressure pump can draw vapor and bubble free fuel from. it has a nedle and seat just like a carb but its vented to the air box or intake depending on design.
its also posible to have a bad pressure regulator.
none of it is hard to check.
if you can make it flood with just squeezing the fuel primer bulb look in the VST, if not cycle the key switch several times. if it floods when the pressure pump cycles its going to be an injector or a pressure regulator.

 

[JUSTINTIME]

Re: Help on 2000 Suzuki DT140 EFI - gas coming out of Throttle body

wasnt aware they made the DT140 in EFI. the DF140 was a 4 stroke EFI.
if.

96-01 rod


VST tank

it could be a bad regulator filling up the vst also, but that is a guess

 

[rodbolt]

Re: Help on 2000 Suzuki DT140 EFI - gas coming out of Throttle body

either way, the line on top of the VST wil be a vent,unplug it. if fuel is running out its the VST needle assy, if not unplug the line on the presure regulator,usually mounted on the fuel rail, and see if fuel is coming out with the engine running or at least the high pressure pump running.
thats the nice thing about speed density EFI, aint but so many ways to make it. only difference is where they locate the parts.
.