Can't figure out why idle is gradually dropping

[pudzley]

Hey everyone... I'm having an issue with my GS after this winter. I confess... I didn't really winterize the bike at all. It sat in my garage from November to late March so I don't know if that's long enough for bad gas to be a factor, but here are the symptoms:

When I start the bike, I use a little choke like always, it starts right up (it's 65deg out now) and it runs kind of poorly until it warms up a bit (tends to misfire right around 1500rpm, but this was an issue I've had for over a year now). However, once it warms up a bit, I kill the choke, and it idles nicely at 1200rpm. The problem is that after 10-15 minutes of idling perfectly, the idle slowly starts to drop... once it starts dropping, it takes about 5-10 minutes for it to go from 1200 to about 400/500rpm, at which point it's barely running and eventually stalls. I can start it right back up with a small twist of the throttle while hitting the starter, it idles at 1200 for a minute and then starts to desend once again. If I give it gas, it seems to rev up just fine, then it comes back to 1200 for a minute, and starts dropping again until it stalls.

The first time I noticed this issue, once the bike stalled after the idle dropping gradually, I noticed fuel dripping from the overflow hose. It dripped for a few minutes and eventually stopped. I suspected perhaps it was a stuck float so I tapped the carb bowls but I don't think that helped anything.

I figured maybe there was some old gas in the carbs so I topped off the tank with fresh gas, put in 5 oz. of Seafoam, shook the tank, and took it for a ride in hopes that a spirited ride would blow whatever was causing the issue through the carbs. Unfortunately, when I got home after the ride, the idle started dropping almost immediately and after a minute the bike was again barely running and died  After it stalled, a few I noticed a few drops of fuel come out of the overflow.

Any ideas as to what might be causing these symptoms? Thanks very much for any advice!

[Suzuki Stevo]

Today's fuel goes to compost very quickly...I think you are on the right track by suspecting the fuel 

[pudzley]

Ok thank you! I will just have to ride a lot tomorrow to get this fuel through the tank so I can fill up again 

I'll post an update after I get the old gas through the carbs to see if that solves the issue. Any other ideas on what might be causing this?

[Janx101]

..... hmmm... just me... but i would drain the old gas out....get as much as you can out... then put in a 5 litre can of fresh fuel (that you prepared earlier) .. and test the theory ... if it is the fuel then you will know pretty quick.... if it ISNT the fuel .. and you have another problem that 'might' be made worse by further use .. then you will know its not the fuel and be able to start working on 'the other' problem sooner!!...

and riding around on bad fuel... what if its full of crud and by further riding you clog the carbs etc with said crud?

bite the bullet and just dump the old fuel!! 

[Paulcet]

Also, with today's fuel, the danger could already be done. The float needles could be worn out.