Hi all, I couldn’t find any help searching for “flooding”, so I hope this new post brings out the best in your knowledge of 2001 Suzuki carbs . Here’s my ATV’s story:
After it was sitting for a couple months, it took a lot of turning-over and full choke to get it to run, which wasn’t normal, but finally it started and I puttered off down a nearby trail. After about five minutes of slow riding, at the dead-end of the trail (of course), the engine faltered, sputtered, died, and would not restart, choked or not. Just like running out of gas, but I had plenty. Different fuel petcock settings didn’t help. It was a long push back.
Air filter is clean, screen at air entry is clear, spark plug is a little dirty but was working, gap is perfect. I removed the carb diaphragm cover (#1 on the carb drawing at <a href="http://www.bikebandit.com/2000-suzuki-motorcycle-ltf300fy/o/m6475" target="new">Bike Bandit</a>), pulled the “vacuum piston/diaphragm assembly” off the top (#’s 2-4), and found the chamber under it, where the #12 jet needle pushes down into a seat, half full of fuel.
After I checked some oil levels and removed and replaced an inspection plug on the front bottom of the carb, the fuel puddle in the carb was now gone. Maybe it leaked down into the exhaust? I put it back together and it started with choke, with very white exhaust that dissipated normally—extra fuel, I guess. As it warmed up and I backed off the choke, it only stayed running if I kept on the gas, which made lots of white exhaust (maybe just because it was fairly cold). It got harder and harder to keep running, and finally I let it die. It won’t restart, and there’s a puddle of fuel in the carb chamber again.
Next I pulled the carb completely out, removed all three of those brass jet port things (pilot jet, etc.) on the bottom of the carb (one at a time!) and blew them out along with the ports they screw into (didn’t have carb cleaner on hand); they were all clean and I could see through all the holes. Float is beautiful, no fuel sloshing around inside, float pin shiny and clean, float moves the needle smoothly. There was very little crud in the bowl, just a little red resin/grit.
There was a tiny piece of hard resin stuck above the needle valve, and I was certain that was the cause of the flooding. Neither the float needle nor the long jet needle (#12 on the BB diagram) connected to the vacuum diaphragm on top looked abnormal. I put everything back together, it started right up even with an empty bowl, and it idled great. Thought I had it licked. Took it for a spin, this time back and forth past my driveway instead of down a long dead-end trail . It ran awesome and made lots of mud…for about five minutes, at which point it started choking. Gooosing the throttle kept it going long enough to drive back into my shelter/garage. Took the carb cover off, pulled the piston valve and diaphragm off, and the bowl was full of fuel again.
A suggestion I’ll pursue next that the fuel petcock might have a hole; after that, I might replace the vacuum needle (#12) and seat. I’ll also add a fuel filter, as apparently this rig doesn’t have one (save $1.50, kill an ATV—I don’t get it). I’d guess the fuel pump should be fine, seeing how quickly it got the rig started with an empty carb bowl.
It only has about 1300 miles on it and was running like a champ last time I had it out, when it started easy, warmed up and idled quickly, and ran great. I can add photos here if that'd be helpful.
I can fix most things I put my mind to, but I'm don't have much experience troubleshooting a carb problem—if indeed it even is the carb, and not vacuum-related or something else. Your seasoned advice (and guesses) welcome!
Many thanks, Eric