it'll start but wont stay on for long

[asscobra]

ok so my brothers girlfreind needed help moving, and in exchange i was given a free honda spree (which is way sweet cause i've been trying to build one/ buy one forever) so i get it and she says "it's been sitting in my backyard under a tarp for years, is used to run great and then my uncle borrowed it and tried to make it go faster by bypassing something and it ran for a day and quit and nobody could fix it"
when i got i all that i could see was that one of the gas lines was disconnected, so i reconnected it, put some gas in it and it started up and quickly shut off, it did that 2 more times the next day and then wouldnt start for a week.
so i rebuilt the engine, cleaned it, cleaned everything else, got the carb spotless inside and out and put it all back together, and it wouldnt stay on for more than a second or 2, so i took it to a friend and he shows me that the pin inside the carb that keeps the throttle from spinnig left and right was gone, so i put a new one in. now it starts and i have ridden in around the neighborhood a couple times except it shuts off anytime i come to a complete stop or let off on the gas and even though i have my hand steady on the throttle it sounds like i am revving the engine from full throttle to nothing constantly
i'm almost positive it has something to do with the carb, and how its adjusted but i cant
seem to get it right so if i am right (hopefully) that is all i need to know. also there is a crack in the gas tank that i havent fixed yet (i've just been filling it up to a little bit under the crack so it dosent leak everywhere) so maybe that has something to do with it? please help, it took me forever to get one of these and get it working and looking at it just sitting there is killing me haha, i just wanna go ride!

[vette76]

i would reclean the carb. u have a filter/airbox rite?

[asscobra]

yeah, i found a website that told me how to clean the air filter so i did that, then i had my buddys dad clean the carb because he knows a lot about them so i'm assuming he did a good job the only thing left i can think of is that the idle screw and the others on there arent adjusted right

[vette76]

u can try to raise the idle. it could be set too low.

[deathwish]

did u change the plug????? always chnge the plug whens its been sittin around for a while...get a few extras u wil probobly need them

[asscobra]

if the plug was messed up or old would it work somewhat and then stop randomly? because if so thats probably it, i just never figured the plug to be the problem because it starts up and idles for a few seconds and then quits on me, and sometimes i can get it around the block or so before it gives up

[vette76]

could be, but the carb is still ur best bet. i would replace the plug either way.

[noiseguy]

Gee, sounds like a plugged idle jet. Tell your buddy to reclean it and make sure the slow jet's clear. You should see light through it.

[burnt_toast]

most likely its the idle mixture, and if its still the old plug DEFINATLEY change that. Mine wouldn't go past 14mph w/ the old plug. Make sure the petcock is working right too, if its not it might be stopping your gas flow and therefore shutting off.