Fuel Dump

[Heath Morris]

I have a 2013 which was being stored at my parents. She has been up on her stands for about 2 months or so and while I was in the other day I tried to start her to let her run a bit and everything was normal except when I released the ignition switch it dumped fuel all down the engine. What could cause this? It only dumps fuel after you realise the ignition switch. Any help would be greatly appreciated.

 

[FlatlandBusa]

Look and see where it's leaking.

It shouldn't do that.

 

[Heath Morris]

I plan to once I get it home or when it warms up. I was just wondering if anyone has experienced that before. At first I thought it was a house but if that was the case wouldn't have just leaked out by now not just keep when I released the button?

 

[Mythos]

The fuel line would not leak bad unless the engine was running. If the pump is not building pressure, it might not leak at all from the fuel line.

That is very strange if it stopped after you released the starter button and didn't leak as it was running. How can you be sure it stopped after the starter button was released? I suspect the fuel line is damaged unless you disconnected it from the fuel pump recently. Then it might just not have been reconnected properly. Figure that out. That's a fire hazard with a running engine.

If it's cold by you, could it be water froze in the fuel system and caused some partial blockage? I wouldn't start a bike in winter if you're not riding it. Condensation is never good. Not running is just fine. It sits in a crate for months without running before someone buys it.

 

[Heath Morris]

Yea the fuel pump would prime everything sounds normal. Sounded like the battery was just to weak to get it to turn over but the second I released the button it dumped fuel and stopped I tried it a second time and it did the same thing. So I'm not sure I'm going to take the tank off when I go back in. It was very strange made absolutely no sense.

 

[Mythos]

OH so it didn't start? Here's what I think might possibly be going on.

The fuel pump primes which begins the process of sucking fuel. Releasing the starter button may activate the pump causing fuel to flow through the line to your fuel rail and injectors. Normally, your engine would be running after you release the starter button so it should need fuel right then to run. If the engine dies or doesn't start on the first try, the fuel pours down the cylinder and ends up in the oil pan (another reason to not start in winter if you don't need to).

My guess is you have ice blockage in the fuel line or rail. There's pressure building up that can't get through. I have no idea where it would spill out of unless there is a leak.

I wouldn't bother with it until it warms up if you suspect ice in the fuel system. I would check the line over thoroughly though incase there is a leak.

The Hayabusa fuel line does not look very reliable IMHO. It has no hose clamp. I presume the fuel feed hose coupler has barbs on the nipple but that seems a bit iffy to me for a fuel line. It's possible the hose got blown off from pressure or it fell off somehow and now the fuel is simply pouring out of the fuel pump pipe when the starter button is released. Just my thoughts. Hope it is something simple like that.

I have a pretty good tutorial on fuel tank removal. https://www.hayabusa.org/forum/threads/gen-2-how-to-remove-fuel-tank.168658/

 

[Mythos]

Also, I started my 14 about a month ago (had to to test electronics) after it had been stored a while. It was about 40° and the bike had not run in a couple months. The battery was fully charged. It cranked over about 20 times before it started and backfired. This backfire has happened before on the first hard start of the season if the weather is cool. It tells me there is fuel getting pumped in there the whole time the starter is cranking. Perhaps yours is barely flowing or not flowing because of blockage and when the starter stops, all that backed up pressure overflows out of a relief valve or something.

 

[Heath Morris]

Ok thanks I'll definitely be checking all that when I go back. My intent was to get it out for a little ride but then this happened. But if it was a house leak wouldn't it have leaked all the fuel from the tank? It has a full tank and only spit out maybe a cup each time.

 

[Mathewrussell52]

Ok thanks I'll definitely be checking all that when I go back. My intent was to get it out for a little ride but then this happened. But if it was a house leak wouldn't it have leaked all the fuel from the tank? It has a full tank and only spit out maybe a cup each time.

No

 

[Mythos]

If the hose was disconnected or had a leak, the hose would empty whatever fuel was in the hose. The fuel tank would not drain at all. I've removed fuel lines from my bikes numerous times and all that comes out is 1 oz. SO if the hose is leaking or disconnected, your tank won't drain a drop. If it did, all the fuel from the tank would drain into the motor overnight by gravity.

A cup is a lot of gas. This sounds to me like it might a normal failsafe system at work (let's hope). The fuel rail or line is plugged and you have 45 psi of gasoline backed up in the pump and system that lays downstream. Bike couldn't start if it wanted to because there's no fuel going in it. You release starter button, fuel pump has backup system to relieve pressure should there be any pressure from a clog. The fuel dumps out of an overflow valve. I hope that is it. You know it's working properly if that system actually exists. I'm just guessing what it might be though. Has to be something like that if fuel is not dripping the whole time you're on the starter which would sound more like a leak to me. This sounds like an overflow.

 

[Heath Morris]

Why not?

 

[Heath Morris]

If the hose was disconnected or had a leak, the hose would empty whatever fuel was in the hose. The fuel tank would not drain at all. I've removed fuel lines from my bikes numerous times and all that comes out is 1 oz. SO if the hose is leaking or disconnected, your tank won't drain a drop. If it did, all the fuel from the tank would drain into the motor overnight by gravity.

A cup is a lot of gas. This sounds to me like it might a normal failsafe system at work (let's hope). The fuel rail or line is plugged and you have 45 psi of gasoline backed up in the pump and system that lays downstream. Bike couldn't start if it wanted to because there's no fuel going in it. You release starter button, fuel pump has backup system to relieve pressure should there be any pressure from a clog. The fuel dumps out of an overflow valve. I hope that is it. You know it's working properly if that system actually exists. I'm just guessing what it might be though. Has to be something like that if fuel is not dripping the whole time which would sound more like a leak to me. This sounds like an overflow.

Let's hope it's a safety feature. Thanks for all the help

 

[Mythos]

I think he will say:

if the hose is leaking or disconnected, your tank won't drain a drop. If it did, all the fuel from the tank would drain into the motor overnight by gravity.

 

[Mythos]

Let's hope it's a safety feature. Thanks for all the help

LOL delayed reaction on the posting!

Sure, man. I hope it is just normal. Try when it warms up or maybe someone else will know for sure what this is.

 

[David Offor]

There are vent pipes built into the fuel tank (on my gen 1), if there is a blockage, then maybe it’s pressurising the tank and forcing fuel, past the filler cap and down the vents and then running down the frame of the bike.
Can you try the bike with the fuel cap released and see if any fuel comes out, as before? Best be ready with a fire extinguisher or marshmallows

 

[VIPER]

sounds like to me you have a return line off.

 

[Mythos]

There are vent pipes built into the fuel tank (on my gen 1), if there is a blockage, then maybe it’s pressurising the tank and forcing fuel, past the filler cap and down the vents and then running down the frame of the bike.

That was my first thought but-If it was the surge hose or the drain hose (as they are called in the SM) the fuel should drain out under the belly pan where the ends of those hoses are located...unless one came off...but then, I'd think the leakage would be constant if gas was somehow getting in them. Nope--I don't see how the fuel pump would pressurize the fuel tank. Seems to me that should suck on the fuel tank. If it were possible to push a cup of fuel back into the tank from the pump, the fuel level in the tank is back where it was before you cranked. No overflow at the the fuel tank cover ring. That is where one of those hoses comes from incase you overfill the tank. Other one is to let air in to displace fuel as it goes down (or up from expansion). On a hot day, The tank might get pressurized from heat expansion in the tank. ..that is if that breather hose is clogged. The tank doesn't leak then, it just sprays a mist at you when you open it or the expansion drips out under the belly pan instead--or both.

Can you try the bike with the fuel cap released and see if any fuel comes out, as before? Best be ready with a fire extinguisher or marshmallows

Could give it a try when it warms up and that ice I think is in there melts. I have overfilled my gas tank at the pump and had some run down onto the hot engine. No fire. Not suggested but you are probably not taking too big a risk on a cold motor. To be safe, take it out of the garage so you don't burn the parents' house down. If that happens, I doubt they will let you store anything at their place ever again. A cup is a lot of gas ----but hopefully it will not spill out of that relief valve I think exists when that theoretical ice I think is in there melts.

If that is it, do a Seafoam treatment. Supposed to eliminate water in fuel.

 

[Mythos]

sounds like to me you have a return line off.

Do Cali models have evap emissions canisters? Is this a Cali model? If so, a whole cup of evap---twice in a row? only when he lets go of the strater button and not before?

 

[David Offor]

That was my first thought but-If it was the surge hose or the drain hose (as they are called in the SM) the fuel should drain out under the belly pan where the ends of those hoses are located...unless one came off...but then, I'd think the leakage would be constant if gas was somehow getting in them. Nope--I don't see how the fuel pump would pressurize the fuel tank. Seems to me that should suck on the fuel tank. If it were possible to push a cup of fuel back into the tank from the pump, the fuel level in the tank is back where it was before you cranked. No overflow at the the fuel tank cover ring. That is where one of those hoses comes from incase you overfill the tank. Other one is to let air in to displace fuel as it goes down (or up from expansion). On a hot day, The tank might get pressurized from heat expansion in the tank. ..that is if that breather hose is clogged. The tank doesn't leak then, it just sprays a mist at you when you open it or the expansion drips out under the belly pan instead--or both.


Could give it a try when it warms up and that ice I think is in there melts. I have overfilled my gas tank at the pump and had some run down onto the hot engine. No fire. Not suggested but you are probably not taking too big a risk on a cold motor. To be safe, take it out of the garage so you don't burn the parents' house down. If that happens, I doubt they will let you store anything at their place ever again. A cup is a lot of gas ----but hopefully it will not spill out of that relief valve I think exists when that theoretical ice I think is in there melts.

If that is it, do a Seafoam treatment. Supposed to eliminate water in fuel.

If the fuel pump out let had become blocked the pump could build up back pressure but for the fuel to be pushed to the top of the tank is highly unlikely, I agree with what you say, it’s a tricky one.
I know on mine, I get constant 42psi, ignition on, cranking and running, so, it’s strange that you only get the spill out, when releasing the starter button because if you were getting 45 psi constantly, you would expect the fuel to pour out, as soon as you turn the ignition on and pull the clutch in?

 

[Mythos]

I know on mine, I get constant 42psi, ignition on, cranking and running, so, it’s strange that you only get the spill out, when releasing the starter button

Maybe Suzuki designed the pressure relief valve to only open if the engine won't start. If there was partial blockage but enough flow to start the engine, dumping excess pressure could cause a fire.

It's also possible that the dump occurring right after releasing the starter button was only coincidental. If he kept the starter button pressed longer, it may leak while cranking.