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I cant get the darn thing to run correctly. It just seems like it is getting too much air because when I start it (usually with a little bit of choke), it'll idle decently, and can even take the choke off and it will still idle for the most part pretty smoothly. But as soon as I give it gas the thing just bogs out. The only way I can get it to run good is if I cover basically 3/4 of the intake on the airbox to restrict airflow, then it will rev up just fine. Little backstory, it's my buddy's father's quad, they took it out one day and it died and they couldn't get it running, so they replaced the carb because that's their standard thing to do when something doesn't work. So they changed the carb and I guess it ran fine with their new cheap eBay carb until they partially sunk it and it died out (it didn't inhale water), and they could never get it to run again without it bogging out every time they gave it gas, which is the same issue I am having now. Both carb boots have been replaced because I found cracks/dry rot in the originals. I believe I have everything cleaned inside the carb after taking it apart and cleaning the ports and soaking it in my parts washer and such. What am I missing? Also I am a little confused on where the vacuum hoses on the carb go. I'm not sure what the original carb looks like as they got rid of it or lost it, but this carb on it now has 2 vacuum lines on the airbox side of the carb, connected with a Y connector and the line is just not connected to anything. There is also a 3rd vacuum line that is on the motor side of the carb (on the opposite side of the choke and throttle connection points) and also looks like it has a filter or check valve with an arrow on it on the end of the line. This line is also not hooked to anything, Is this normal? Either way blocking these vacuum lines doesn't do anything to make it run better. Can anyone offer and ideas? Thanks
Ive never used a parts washer to clean a carb, not sure it will clean it well enough. Verify with aerosol carb cleaner, and compressed air that all the passages are clear(even the passages in the back of the carb) Make sure the diaphragm isnt torn or will turn on the slide.
The fittings on the back of the carb are actually vents. They are usually connected with the "Y" so no problem there. The one on the front is probably because its an aftermarket and not needed on this unit. Just plug it off. Try spraying carb cleaner around the boots, carb etc and see if the motor changes rpm indicating an air leak.
Question - The air box lid in installed and it still runs bad? These units dont run correctly with the air box lid off.
I use the parts washer because it’s heated and has been decent at cleaning things in the past and the cleaning agent in it is very mild, but I also spray the ports with compressed air. I just don’t know where I am supposed to be seeing air blow through for each of the ports. I just took it out to clean again to see if I missed anything and took the jets out and all seems clear.
I have not tried spraying carb cleaner around the boots yet again but I suspect that there should be no leaks as both boots are new, and by the amount I have to cover up the intake for it to run decent there would have to be like a half inch hole in one of the boots to be sucking in that much air to mess it up.
I am running with the air box lid on, I am actually having to block like 3/4 of the mini snorkel coming off of it just to restrict airflow enough to have a mixture capable of revving it up and such.
I just cleaned the carb again, maybe I missed something the first time when I did it, but I’m kinda doubtful.
I’d say it’s a lack of fuel and the normal amount of air is just too much for a good ratio, but it revs up powerfully while blocking the intake a bit like it’s just taking in way too much. Idk I’m stumped, I’ll install the carb again and see what happens
I use the parts washer because it’s heated and has been decent at cleaning things in the past and the cleaning agent in it is very mild, but I also spray the ports with compressed air. I just don’t know where I am supposed to be seeing air blow through for each of the ports. I just took it out to clean again to see if I missed anything and took the jets out and all seems clear.
I have not tried spraying carb cleaner around the boots yet again but I suspect that there should be no leaks as both boots are new, and by the amount I have to cover up the intake for it to run decent there would have to be like a half inch hole in one of the boots to be sucking in that much air to mess it up.
I am running with the air box lid on, I am actually having to block like 3/4 of the mini snorkel coming off of it just to restrict airflow enough to have a mixture capable of revving it up and such.
I just cleaned the carb again, maybe I missed something the first time when I did it, but I’m kinda doubtful.
I’d say it’s a lack of fuel and the normal amount of air is just too much for a good ratio, but it revs up powerfully while blocking the intake a bit like it’s just taking in way too much. Idk I’m stumped, I’ll install the carb again and see what happens
My idea of parts washer was a solvent tank, yours sounds good. I use a heated ultrasonic myself. Its hard to explain where air pressure should exit from but if theres a hole, usually they go somewhere so see if you can hear air coming from another spot on the carb, when blowing air out. Rubber tipped air gun works well for this.
After approx 1/4 throttle, the main jet, jet needle, needle jet and slide comes into play in the carb. Id focus on that portion of the carb.
Not sure if this video link will work but this is revving it with and without blocking the intake. (Not sure where to upload quick videos with URLs these days lol) View My Video
Cleaned the carb a second time and I’m pretty sure the thing is clear. I just don’t know what the heck to check anymore
Robbing more pics from the net. I know you have cleaned the carb and probably very well. I'm not arguing that point. Did you verify the passage circled in red is clear? I have seen people clean the carbs very well and focused on the internals in the bowl, and overlook the air passages in the rear of the carb. There are a lot of carbs out there and some have pipes that go places, others have pipes that dont go anywhere. With out your carb in my hand I cant guarantee yours goes anywhere. If it does however have a hole in it, they can get plugged up, causing no air to enter the emulsion tube and not pull fuel correctly. Could cause issues. If its clear I'd stick a bigger main jet in it and see how it runs.
10-29-2018, 07:36 PM
2004 Sportsman 700
