2000 suzuki king quad lt-f300f idle issues

[johnwayne]

i have a 2000 suzuki king quad lt-f300f that i picked up as a project bike. it didnt run well when it was parked outside 5 years ago. it cranked after putting fresh gas - but would not run below half throttle, i took apart the carb, cleaned debris, and re-assembled. i suspect that the pilot needle is sheared off - it never protrudes into the throttle body through the pinhole. now to get the bike to ALMOST idle, the throttle idle adjustment knob is all the way up/in. the pilot needle is turned almost all the way in/up (if i understand correct, it should nominally be out 2 1/4 turns or so). and like i said, it will ALMOST idle. floods easily, rides rough.

wanted to hear from those more experienced than me with suzukis - and im self-taught atv repair, so dont laugh too hard if my verbiage/part names is way off. 

facing the driver's side of the bike [US] there are three hoses on this side of the carb. without a service manual or way of knowing what was messed up before i got it, i think i have them right: front hose as a vacuum to the petcock, middle hose as vacuum to the fuel pump, rear hose as fuel line from the fuel pump. running the bike in prime position results in flooding even while riding. with all hoses disconnected from the carb, fuel slowly drips from the vacuum line connected to the petcock.

so just my speculation is that the diaphragm in the petcock is split, and the pilot needle is broke off - causing my inability to not quite idle and the rough ride. this suzuki is hoses and cables everywhere compared to the honda ranchers and yamaha warriors i am used to. I would like to have a plan rather than: replace everything at once.

is my speculation on the right track, or could something else be at play? say, if the compression was non-existent, would that cause non-idling? i am all ears, look forward to the input.

[johnwayne]

upon looking at carb diagrams, seems that there a bunch of o-rings that are missing. perhaps that was the debris i got out of the bowl. if thats the case, ive never seen o-rings breakdown like that, but it's a wonder the bike would crank at all if the o-rings are necessary to the fuel routing. probably gonna replace the fuel petcock as well. how can i check the fuel pump?

[Coyote251]

If you have fuel coming out the vacuum line on your petcock, you are right that the diaphragm is shot. I am going through the same issue right now on my 01 LT-F500F, I have the vacuum blocked off and am running my bike in prime for now until I can get a new fuel valve assembly.

Carb kit for my bike was 15$CAD on ebay, took a month to get here from China so I ended up going to the local shop and buying one for 30$CAD. I would suggest you pull that carburetor off, get it all apart and soak it in something like Hydro Seal (not sure what's available in the USA, but that's what I use). Then clean out every little port, I use different guitar strings for the different size ports and a lot of compressed air and carb cleaner. Once you have done that, soak it again and clean it again. Sounds to me like you have a problem in the pilot circuit. When you put it back together pay close attention to your float height and make sure it is set right. Not sure what that spec would be on your bike, it's 13mm +/- .5mm for mine.

Go to the downloads section and there is a manual there for LT-F500F, it's got a good explanation in there of how each of the circuits work and what circuit is responsible for what stage of idle.

I'm not sure about the lines on your carburetor. My bike has no fuel pump, it has a straight 6" hose from the petcock to the carburetor. I then have 2 vent lines on the top left and right and the vacuum for the petcock on the crankcase side.

The pilot screw adjustment for my bike is 2 3/8 turns out from a soft seat (as per the manual)

Not sure if any of that helps you.