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Oh NOo! Fuel flooded Engine!!

  • Thread starter Thread starter grips11
  • Start date Start date
G

grips11

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What is the best remedy for a fuel flooded engine? :oops: I've had bad weather here for about 2 weeks. Today the sun was shining and desided to take out the bike. On the road i notice the my bike's just not sounding or running right. It would stop running in 1st gear and the engine was making funny, not normal sounds, and it just wasn't shifting right. Took it home and noticed that I had fuel leaking out of my airbox vent tube. The obcious reason for the flood is that I didn't turn off the fuel before the rain hit. I thought i did but there is no "off" on my fuel petcock.:-s Only "prime", "on" and "res". go figure?
 
Make and model of your bike would be helpful.

First of all, if you got a lot of fuel in your oil, you should probably change it.

Secondly, when your petcock is turned to "on" and the bike is off, no fuel will flow because there is no vacuum being applied to the petcock. Its designed that way so that you won't forget to turn the fuel off when you park your bike. Reserve functions just like "on" except it will use all the gas in the tank.

Fuel will flow to the carbs when its set to "prime" however at all times. This is so if the bikes been sitting for a while you can get some gas in the carbs to start it.

So you either left the bike on "prime" or your petcock is not working properly. Pull you vacuum line and suck on it with your petcock set to "on". If fuel flows its working O.K., if not you need to fix it.

Another problem could be that your float valves are not seating properly or your float valve o-rings need replacing.
 
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Great advice! Ok, the carbs have been professional cleaned and set a few weeks back so I know the carbs are fine. I'm ashamed to admit but I left the valve lever poistioned inbetween "prime"and "on" b/c positioned here I thought fuel would be blocked from flowing....we all have our dumb moments, However I had no idea about the tech specs of the gs petcock. Thanks for the info once again. now I know. Ok, so I think im going to have to change the oil. Should I do anything else? Like soak out the air box? or air filter? Once I get the oil changed is it safe to start the bike again?
 
grips11 said:
Great advice! Ok, the carbs have been professional cleaned and set a few weeks back so I know the carbs are fine. I'm ashamed to admit but I left the valve lever poistioned inbetween "prime"and "on" b/c positioned here I thought fuel would be blocked from flowing....we all have our dumb moments, However I had no idea about the tech specs of the gs petcock. Thanks for the info once again. now I know. Ok, so I think im going to have to change the oil. Should I do anything else? Like soak out the air box? or air filter? Once I get the oil changed is it safe to start the bike again?
Click to expand...

Check the filter, if its a stock filter and looks O.K. you shouldn't need to change it......even though I probably would if it really was gas soaked. Maybe wipe out the air box and check your airbox seals.

But there shouldn't be any danger in starting it once you've changed your oil. Maybe someone else would chime in with something different, but with an oil change you should be good to go.
 
Ok, I've changed the oil and my bike is still spitting out small amounts of fuel. Anyother suggestions? Is there a way I can get the excess fuel out of a flooded engine w/o taking my bike apart? [-o<
 
If you are getting gas in the oil you have several problems. 1. Your float levels might be off. 2. the O Rings around the float valves might be flat and wore out. 3. Your petcock has a problem. Did you test the petcock as described above. You should be able to suck on the little hose on the petcock and it should maintain a vacuum and hold your tongue with the vacuum. If you can suck air or gas thru that little hose the petcock needs replaced. The kits are crap more times than not. If fuel runs out the bigger hose when your NOT sucking on the vacuum hose and the petcock is set to run, it is shot and needs replaced. If you getting a raw gas smell out of the exhaust it's a bomb looking for a spark.
 
:confused: Before the bad weather hit I was riding my bike and everything was working great, and I just had my bike looked at by my mechanics. I left the petcock on prime when i stored it ( b/c at the time i didn't konw any better:oops: ), hence the flooded engine. Petcock and carburator are functioning as normal. I think my only issue now is getting All the excess Gas/oil out of the engine. I've left the air filter and spark plugs off and out of the bike. My hunch is that maybe I should drain the oil once again and let it sit dry for a night. All advice is welcomed
 
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Well, first how much is still spitting out? And were is it coming from. Did you chang the fillter with the oil? Gas makes a horrible lubircant for the engine! Depending on how much gas was in the oil you should change it once more. I would run it easy for a bit to get the remaining gas out. The gas might have been up in the heads. Oh, one more thing make sure petcock is working right, if not it might not be stoping the gas even if the leaver is only on "on" or "rev". some one corect me if wrong.

good luck
 
](*,) *smacks my forhead* no i didn't change the filter along with the oil. ...i'll make a mental note of that. On to the next subject, the fuel is spitting out of the Airbox vent tube. Whats comming out is not a whole lot. Theres just enough in there to make the engine die abbout 1 min after idle. So after i changed the oil the first time I drove my bike around the blocki noticed that it was still having problems...like stalling after downshifting. I've heard that starting a flooded bike and running it is bad. I didn't drive it too long however. It did stall out on me just as I was pulling it into the drive.
 
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First off, if a carb is flooding the problem should not be the petcock, even if left in the PRI position the floats in the carb bowl should be able to stop fuel from entering. It should be a float/carb problem. I had the exact same problem a couple weeks ago. I took the airbox off and watched to see which carb was spitting fuel (turned out to be #2). I had recently cleaned and rebuilt the carbs. I took the carbs off the bike and examined #2. It turned out that the float was getting stuck low in the bowl and not able to stop the flow of fuel. I re-cleaned the carb and installed an in-line fuel filter just in case particles from the 25 year old gas tank were getting in the barb (Napa has a 5/16 ID inline that works well). No more engine flooding. I did change my oil before riding. Each carb has a screen that acts as a filter befor allowing fuel into the bowl, you should make sure that all the screens are still there (see the carb re-build guide on this website). You can alse see if a float is stuck by removing the bowl and bouncing the float around.
 
Gravity will drain the gas out of your engine the first time so this isn't the issue. Ask your mechanic if he replaced the float needle seat o-ring. Also find out if he used aftermarket rebuild kits and used them for new float needle and seats. Alot of them are crap. Also did he measure the float heigth.
Pull the small hose off your petcock and see if there is gas in it. If there is the petcock is toast.
Also there might be some gunk in the float needle seat and it isn't letting the float do its job.
 
Chef, you are 100% right about the floats and a little bit of dirt not allowing the needle to do its job. I had a running problem with that on Suzie Q until I installed my new tank. I had so much crud, and that is after cleaning the tank several times with alcohol etc. that I could pull the carbs "clean them out" and have them back on in about an hour and a half. That method cost me new cables and undue ware and tear.
That said, he could still have a valve problem and it is easy to check. Pull the fuel line at the valve and replace it with tube that can drip into a pan. If the valve isn't already running gas that is. The diaphragm can still function and the valve pass gas.

If the valve is leaking, try this. Drain the tank and remove the 2 bolts holding the valve. On the back of the valve is 4 screws, that is the vacuum side of the valve. Remove the screws, be careful, there is a spring ontop of the diaphragm on the vacuum side, if it doesn't come right apart, replace a couple screws a couple turns and give the seam a rap with the but of a screwdriver.

With the back off inspect and clean it and carefully remove the diaphragm. On the fuel side is a stud with an O ring. Check the O ring for crud that would keep it from seating. If the O ring looks worn, carefully remove it and turn it over, it works trust me.

On the valve side, check the chamfered seat for crud or corrosion, clean as necessary. Turn the valve and watch its function. There is a little brass nip that actually in prime contacts the O ring stud and lifts it, thus opening the valve.
Turn the valve to on and reassemble in reverse order.
That should fix the leaky valve.
If a carb is dumping gas, it has to get it from somewhere.
Gustov
 
Canned reply...

Canned reply...

First, let me point out the obvious: If a carb (or carbs) are overflowing when the bike is not running, you have TWO problems. First, your petcock should prevent ANY flow; second, the needle valve should allow flow only up to a fixed height in the bowl (ie, not overflow). Excess fuel has to make its way past both of these parts.

(A third possibility on old carbs is for fuel to flow past the inlet seat O-ring. [n/a for VM]. That doesn't apply to newly rebuilt carbs, since the owner has just installed brand new. Right??)

I'm not 100% sure why some needle valves leak and others don't, but I'm starting to lean with Keith Kraus' suggestion, which is to use only OEM valves and seats. Simply because it works. The question why is a separate matter. (I have a theory, but no guinea pig to test it on at present).

For the petcock, you'll hear a number of suggestions. I think that the vacuum operated petcock should be kept operational, for a few safety reasons.

Several of the folks here are convinced that petcock rebuild kits are useless, and your only real option is to buy a new OEM petcock.

For now, for people who are 100% sick of carb overflow & the ensuing problems, the consensus then is to go with OEM petcock, seats & needles. it's expensive, but it seems to be the only certain way to correct this BS once and for all.

(I would add: no doubt there are people whose overflow problems began when they bought carb rebuild kit(s). The machining on the parts is often abhorent and inexcusably amateurish, and the f&^%#ing O-rings don't fit correctly. The consensus for a while now has been to buy gaskets IF you need them, valve seats & needles IF you need them, and an O-ring kit.)


The petcock does not, in any way, REGULATE the rate of flow. It should be either on or off. If you have overflow on a running bike, there's a problem with the inlet valve.

Either:

1) the float is no longer buoyant enough or is badly adjusted, or

2)the valve is bad, or is being held open by some foreign matter.
 
Everyone these are great responses. keep it up! Ok, I've got alot to do starting with re-draining AND changing the filter!! I will post again asap! [-o<
 
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Follow up on flooded engine

Follow up on flooded engine

So this morning I did a couple of things...I figure i'd go ahead and do a process of elimination before I take apart my carbs and/or petcock:

1st I emptied the bike of oil and replaced the old oil filter. The bike still does not have any oil in it at this point. the bike is "dry". however there is fuel in the tank.

2nd I drained the carb float bowls(x4) of gasoline. I figure the engine may have enough in it already. i dont want anymore getting in there.

3rd I performed a makeshift test on the carbs and petcock. I left all four drain plugs off the carbs and made sure the carbs were finished emptying fuel from them. Nothing was coming out of either of the bowls anymore. Then, I turned the petcock to "Prime" and sure enough fuel began to flow from the bowls. ok. Then I turned the petcock back to "ON" and the fuel stopped flowing out of the drain plugs.

Having done this simple test I figure that the petcock is working as normal and I believe my carbs are working as normal. I will leave the bike dry for the night. In the morningi'll check to see if anymore oil wants to come out from the engine before I add new oil. I hope this works.[-o<
 
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