I'm having a similar problem... I just bought a used 04 predator 500. This is my first ATV, so I'm now getting a crash course with maintenance, repair, etc. It seemed to run fine when I first bought it, which was about 3-4wks ago. I took it on my first long ride soon after I bought it... The first thing it kept doing was stalling intermittently when coming to a stop. It would always start right back up, so I didn't care too much at the time. About an hour into the ride, I hit a small mud hole. Almost instantly I could feel a slight hesitation and a little backfiring. I really don't have a clue as to how this could have caused any problems because this was more mud than water. Also, not sure where it could have been sucked into the engine/carb? It seemed to run fine for another 45min or so, then finally bogged down and stalled. When trying to start it again, it kept sputtering and backfiring. It didn't want to start... I finally got it started and had to keep the throttle open so it wouldn't stall. Needless to say, I barely made it home.
So, here's what I've done so far.
- New air filter
- New spark plug (gapped to proper specs as well)
- Strained gas tank, which was full of garbage...
- Added SeaFoam to gas.
- Installed a rebuild kit, and new o-rings throughout. New jets, needle, needle seat, etc.
- Cleaned out every hole on the carb with cleaner, soaked in hot water, blew out with air.
- Checked float height and made sure float moves freely.
- Removed the pilot screw and cleaned. Also placed an o-ring on it too, since it was missing when I removed it.
- Installed filters on the two vent hoses coming off the carburetor. Not sure if that's a big deal or not, but I read where it could cause problems.
So I literally JUST got all of this done over the weekend. Had everything put back together and was ready to try it out. Took it a while to start... Just kept turning, so I sprayed carb cleaner into the carb to help it out. It started and seemed to run excellent. Rode it for maybe 10min, and all seemed well. The next day, was going to ride it a little harder to make sure everything was good. It started right up and idled great. While riding, I was giving it lots of gas to see if I could detect loss of power or sputtering. Just short, fast bursts. Never really got out of third gear. After 5min of riding like this, the sputtering started again. Freaking pissed me off... Not much longer after it started, it died. It wants to roll over while trying to start, but never cranks. It might rev up a little, but instantly dies. Checked the spark plug last night and it's a little black. It's not charcoal black, but definitely sooty. SO... Here are my questions.
1) Is it flooding or am I not getting enough gas? I really can't tell. I know my float bowl is full of gas, so I'm assuming it's flooding... Thoughts?
2) Is my fuel pump bad? The gas flows great from the petcock to fuel pump. I took the line off the carb last night and tried to crank, but no gas came out. I read where I should get a steady stream of gas... Is this for when the engine is actually "running", or should it do the same thing while attempting to crank? I also checked the vacuum line for obstructions. All the lines seem okay.
3) Could my gas cap vent be clogged? I haven't troubleshooted this yet. Wasn't sure if a clogged vent could cause those problems.
4) My e-clip is on the 3rd notch. Would adjusting the clip help? I'm really not sure if my problems are from running too rich or too lean, so I don't know which way to move the notch.
5) Could my valves and/or timing cause these problems?
6) Compression? I don't have a compression tester, but was wondering if this could be an issue too.
We’re you ever able to find out your problem, dealing w same thing
Sorry for the loaded questions, but I'm at the breaking point... I've ridden this lemon 6 times and it's killing me to see my money go to waste because it's not running right! Even if I wanted to sell it and buy something better, I can't sell if it's not running.
Any help or advice would be greatly appreciated! Thanks in advance. Brion