Fuel in airbox... leaking and flooding!!!

[Anonymous]

Hey. I have just rebuilt a set of carbs for my gs550e (1981) and they were running great for a week. Then a couple days ago I am riding and all of a sudden it feels boggy in the midrange. At a stoplight I smell fuel. When I pull over I see that fuel is leaking out of the airbox boot behind carb 2 and that fuel is coming out of the airbox drain.

I get her home and check it out. I can't get a decent idel and fuel is *@%^$*@%^$*@%^$*@%^$ing out of the dang thing. I pulled the lead to spark plug 2 and the idle doesn't change. Seems like it is flooding on carb 2 me thinks. I pull the carbs to examine the floats. They are all at the right height and they move freely. What else should I look at?

I am confused and frustrated and I am staring at these suckers in bewilderment right now... Please help!
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[gspaul]

Has to be the float needles and seat's,either worn or dirty.

[ChinsyJones]

Replace the O-ring on the needle seat assembly, I had simaliar issues, ordered all 4 of from a local suzuki dealer, replaced all & no longer a problem.. also make sure the petcock is not on prime.

[Redman]

Havent had this experience myself, but I understand that the vacuum operated petcock (assuming yours has a vacuum operated petcock) has the vacuum line getting the vacuum from #2 carb. If the diaphram in the petcock is damaged/cracked then #2 carb can suck gas from the petcock.

Maybe try this: Disconnect the vaccum line from the petcock (its the smaller of the two). See if it runs better that way. May need to plug the vacuum line, and will need definitly to have the petcock on "prime" to get it to run at all. Again, this all assumes that your bike has a vacuum operated petcock, and the problem is specific to #2 carb.

And/or problem can be the float valves in carbs not seating (not shutting off).

[Anonymous]

ok. My petcock is working. I replaced the diaphragm on it two weeks ago because is was messed up. Plus I do all my testing on an auxillary tank I built out of a coolant runoff tank.

I replaced the o-rings on the needle seats after reading this post. Of course, I thought! I have a spare set laying around so I just popped them on. Fuel still comes out of the air box and the idle slowly dies. It is firing on all cylinders though. Why is too much fuel coming in? Now remember. This problem didn't happen a week ago. So what could it be?

I have three sets of carbs for this damn bike. One of the differences between them is that on the float needles there are little wires that seem to hold them in. They attach to the needle baskets. Do I need those?

Thanks.

[kalessin]

It may be worth checking that the diaphragm in the petcock isn't installed backwards. I did this once on my old GS650GL, and had gas overflowing the carbs...

[Anonymous]

I installed the diaphragm right. It tests fine. Plus this problem with my carbs happens when I use my auxillary tank.

[DaveDanger]

Candide, being unfamiliar with the exact layout of the 550's carb setup, I'm not sure how my advice will apply but... on my 81 GS850GLX, there a pair of vent tubes that connect to tee fittings between the pairs of carbs, in other words a tee between 1 & 2, and a tee between 3 & 4. The best that I can determine, the vent hoses simply run over the top of the airbox and hang down towards the ground near the rear tire. These vent lines are very important to the float bowl's proper operation. I inadvertently plugged these lines at one point, and all 4 of my carbs gushed fuel into my airbox. When I opened the lines, they stopped flooding. I didn't explore any further into the exact plumbing of those tees and how they vent the float bowls, but I'd be willing to bet a dollar that the vent on your #3 carb is plugged or restricted internally. Check into the vent orifice on your #3 float chamber and see if cleaning that helps any.

[Anonymous]

Dave-- i will definitely check that out. My vents are hooked up properly but I will check and make sure the vents are flowing.

So she is running okay except for the flooding... it iw wierd. There is a definite bogginess at about 1000 to 3500 rpm but then it opens up. If feels flooded at that range. I am really a junior when it comes to the operation of carbs. Is there a separate element that keeps fuel in there at low rpms? Because it would seem that my floats are doing a fine job if fuel is fed a normal rate in the higher power bands. It isn't starving on the freeway but when coming away from a stoplight, I have to play the clutch to get out of boggy soggy land. Any ideas?

[ccratin]

Is the choke stuck open?

[Anonymous]

The choke seems to be closed all the way. Maybe it is stuck open or something... what can I check?

[ccratin]

Actuate your choke while looking at the choke rod to make sure there is movement. Not sure if your choke is right next to the carbs or on the left handlebar controls. Sometimes the cable gets disconnected or broken and doesn't function properly.