carb pissing fuel?

[Rooster85]

took the scoot to work today, during lunch i noticed a unfamiliar sound, like a tapping noise but rpm nor speed effect the sound. i heard it more so at idle and low rpm. when i got off work i cruised home and got the scoot on the jack as soon as i got home, i checked the oil level and it seemed high , level was about an inch above the cross hash, oil had a fuel smell to it. right when i was checking the level and doing the smell check the carb started pissing fuel, a stream from somewhere couldn't tell where, the stream stopped about 15 sec after it started, it appears as tho it was on the left side of the carb (as you are looking at the carb). i took the air cleaner off and inspected the carb i can not tell where it came from but i can say that it defiantly had pressure, i also let the bike sit for about 2 hours then restarted it ,ran fine minus the unusual noise. i am definitely going to change the oil, but what on the carb do i need to look at?

[Shotround]

probably carb puke. close the petcock.

[Rooster85]

it was closed when it did it, any time i stop for a period i close the petcock

[Shores]

You are having carb puke. Turn the pet cock off about 20 seconds before you shut the engine off so you can create expansion room in the carburetor bowl for the expanding fuel due to heat. Or go pumpless and get rid of the problem. If you have been checking your oil with the dipstick and adding oil, you have probably overfilled the engine. These engines do not use or leak oil and the dipstick is notoriously inaccurate. There is a specific method on YouTube for checking the oil but there's really no reason to do it. Put in 4 quarts of oil at oil change and don't check it until you change the oil next time.

[Rooster85]

thank yall,

[moose]

When turning on the ignition how long does the fuel pump run for? it should run for about 5 seconds or less to fill the float bowl, when the engine fires the pump will run as the engine requires more fuel, is sounds to me like its flooding the carb, either the fuel pump is over pressurizing the carb by continually running or the float needle is not seating good enough and flooding the carb, it may seem to run rich, when the engine is off it sounds like the fuel has been leaking through the carb into the inlet manifold into the engine

[shk1968]

So...I recently experienced this Carb Puke thing for the first time, and then a second time shortly after, since I've had my bike (3 yrs. now). I understand the reason for it, but don't understand why it hasn't happened in the 3 years prior? Same hot & humid climate, same riding pattern, same this/that, with one exception - I took off the stock mufflers and installed aftermarket mufflers a few months ago. I did not re-jet the carb and the bike runs great; maybe even better, and sounds great too. Could this be this cause? Could it be running a little hotter than usual? I don't know; just trying to come up with an explanation.

[davej]

could be running a little hotter with the exhaust change. Do you also have a K/N style aftermarket air filter? If so it will need to be rejetted. other than that either insulate the steel line going to the carb or change it to a rubber fuel injection hose and can even insulate that.

[Ratl]

I agree, it is probably that your new exhaust has the area around the fuel lines between the pump and the carburetor running hotter. The pump doesn’t allow the fuel back into the gas tank and the fuel lines get hot, so when the gasoline expands, it has nowhere to go but past the fuel inlet valve. And then overflows out the back of the carb all over your engine and transmission. A number of people have lost their bikes due to fire because of this.

The gas does not go into your engine or oil storage.

I was dealing with carb puke since I got my bike new in 2005, until I went pumpless when my pump crapped out at 18,000 miles. NO REGRETS!

There are only two solutions.

1 - Turn off your petcock 20 seconds or more before you turn off the engine. This allows the lower level of fuel in your bowl, so the fuel has room to expand into it without overflow.

2. Go pumpless. Yes, there are steps involved. You can do them yourself for less money than it costs to buy a new pump. You’ll need a few parts and a little know how, but once you do it, you’ll find that gravity will never fail you. Also, it opens up the whole left side of your cylinders for a better look and a cooler running engine.

[brianmac]

carbs need to be cleaned and inspected every so and so. if it pissed out like a water pistol, its probably the fuel inlet connection at the carb has hairline cracking, hell, its old. i dont buy into the carb puke thing. a small carb in betwixt 2 big ass jugs can get hot, especially if not jetted or if owners blocks air flow . all my RSs oil always smells of gas. cant use dipstick to measure with any degree of consistency. these bikes/carbs are in their 2nd and 3rd decade now.

[Ratl]

Yup. I’m with you. I don’t buy into anything I haven’t personally seen or experienced. Of course, that makes it kinda hard to breathe since I haven’t seen air and therefore don’t believe in it.

As I stated, my carb was puking gas when it was a few days old. No hairline cracks. No improper connections. My Roadstar had less than 1 mile on it when I bought it and I experienced my first puking incident on the first hot day I rode it. It took me quite a while and finding this site with others experiencing the same thing, sharing solutions back and forth to understand what the problem turned out to be.

Don’t pretend you know more about a problem you haven’t experienced and haven’t actually tried to solve. I know you think the engineers at Yamaha can do no wrong, so it has to have a pump if they put it on there back then., Well, then why did they go to fuel injection? Why, because it was a solution to a number of issues they were having (including carb puke) that they implemented later on.

BTW, all carbs are jetted.