I want to start by saying I don't know squat about working on 4-wheelers. Please bear with me when I use the "wrong terminology" or poorly explain myself. I really need some help from the experienced folks out there. I'll start by explaining the important things.


I have a 2000 Suzuki LT80 for my daughter that I bought a couple years ago. It's the Canadian model. It had problems last year with the "thumb throttle" sticking, but it would only be the first 10 seconds of riding it and then be fine. I sprayed some grease down the cable and hoped for the best. Then the quad sat all this summer without getting ran. I started it about a month ago and the thumb throttle stuck majorly. I had to hold onto it for dear life and quickly shut it off. I replaced the throttle cable immediately thinking this was the problem.


With that replaced, the thumb throttle is moving freely, cable is moving freely, but when I started the 4-wheeler, it still tried to take off on me. Then I thought that maybe the "needle jet spring" was wore out in the carburetor so I replaced it. Now I can't get the thing to start at all! I checked the sequence of putting the carb's "needle jet assembly" back together and I am good there. I checked the spark plug... it has spark. The gas in it is only about 5 months old so shouldn't be any issues there.


If it helps, here are a couple of things I thought I should mention...

I never did anything with the petcock during any of this troubleshooting or maintenance. The petcock on it has RES, FUEL, and PRIME. I've never messed with this and honestly don't know when to, unless I ran out of fuel. It's always been facing up, on FUEL, since I bought it. Have I flooded the engine from not doing anything with this? How can I check/ fix this if so?

Just so I could see how the whole "needle jet assembly" sits down in the carburetor, I removed the air inlet hose in front of it. It doesn't seem like that whole assembly lets the jet needle seat all the way down, but maybe that's supposed to be like that?

There is still a lot of room for the "thumb throttle" to move, but the throttle cable and "needle jet assembly" only let it go so far. Is this normal?


Any feedback would be appreciated. Trying to keep from taking this thing into a shop.

 

Why ask again? We answered this as best we could a week ago.

 

I apologize. For some reason my phone wouldn’t let me reply to your comments last week so I just posted it again hoping for more suggestions. While I appreciate your suggestions, those were things I had already tried with no luck. Do you have any other thoughts on what the problem could be? If not do you know of any other forums I could pose the question on?

 

When the throttle is set for idle there is usually about 1 to 2mm gap between slide bottom and carb, but few slides are flat bottomed so it isn't that easy to tell. If the gap is way more than that, I would remove carb and check what is going on. A pain I know as Suzuki made carb removal as awkward as possible. I have a sawn off screwdriver to remove the awkward screw once it has been slackened off slightly with an open ended spanner. Refitting is worse, as that spacer tries to drop out as you fit it, as does the rubber ring.

I often start recalcitrant two strokes using a squirt of gas from a gas blowlamp, less likely to dry the cylinder walls than easy start and, if you over do it, it doesn't wet the plug, just disperses until the mixture is "right" for starting.

 

There’s no spring in these photos just to make it easier to see the slide. So here’s where I’m at… when it’s all assembled the thumb throttle only moves a 1/2” max. Is it possible that I need to lengthen the amount of bare cable that’s able to go down into the slide? Assuming they make new cable crimps to do this.

 

I guess the makers could have got cable length wrong, check against the old cable. Also be sure the crimps are not too big for their seats. I have come across some that don't sit right down in the adjuster, usually on new Chinese carbs coming with wrongly made adjusters. However best to check if the slide is actually sitting on the slow running screw in the carb and there is a bit of slack in the cable before thumb throttle starts to pull at it and lift the slide.

 

Will slide go all the way down without cable installed it? I notice in photo the brass jam nut isnt down so I would turn the brass cable adjuster down all the way also may sure throttle limiter stop isnt adjusted to limit throttle from full movement and yeah will need to have that spring installed to help with throttle return

 

This space here is all that the thumb throttle will move. The adjuster screw at the thumb throttle is backed all the way out so unfortunately that’s not the problem. If I just drop the slide down in the carb it goes all the way down inside and bottoms out. I thought the throttle cable was the exact same length as the old one… before I threw the old one away 🙄. I can’t think what else it could be.

 

Turn brass nut all the wat to the brass cable guide in this photo and then turn the brass cable guide shown in this photo all the way down to the slide cap nut that may give you more movement

 

I tried this but the slide and needle are still far from sitting all the way down into the carb. When I start it up, it just goes into full throttle. I’m tempted to buy an OEM throttle cable and compare to this one I have.