Hello I have a bit of a issue with my quad now I'm not 100℅ sure on the size or the model was my uncle's old quad not mine,but could find it out easy enough it's a full sized quad so 300 or bigger year around 96-2000. Anyways I pulled it out of the barn after sitting for 2 years cleaned the carb, put fresh gas in, checked spark, did all the fun stuff and got her to fire up runs great that is until it runs for 5-15 minutes and will stall out u can give it gas when it wants to stall or choke but it won't save it. But u can fire it right back up immediately and take it for a spin around the yard it will run for another 5-15 minutes then will stall out again. So I checked spark to see if colour changes from when it's cold to when it's running hot and spark is really good blue colour, checked the bowl in the carb when it dies to see it there's gas in there and there was, blew all my lines out made sure nothing was plugged and still same stuff I sat all day trying to figure this thing out and it's passed me. Any ideas on what I should be checking for?? Thanks hope we can get this figured

 

Sounds like an intermittent fueling issue. The first thing I would check when it stalls, immediately Crack open the fuel cap. Do you hear air hissing back into the tank? If so it is a blocked vent or vent line for the cap. Another thing to check is that there isn't still crud in the tank itself that is randomly clogging the fuel system.

 

Thanks for the reply scooter I just finished testing that out and didn't do anything all the lines are clean for the cap. I think ima see if my buddy will let me try his carb off his quad see if that does anything

 

I'm with Scooter...sounds like fuel delivery...I'd pop the fuel line off the carb and verify good flow for the time frame you described above.


If that checks out I'd crack the bowl open and inspect the float and float valve...almost sounds like it takes too long to fill the bowl while running, but given a bit of time it fills and can run again...if the float is kinda getting stuck and not opening fully I could see the symptoms you are describing...

 

Well figured it out but would like someone explain why it does this. Gotta working on it again today and realised when I leave my battery charger on the battery it will idle all day long and run like a charm but when I take them off it will run for the 5-15mins then idle really high and stall out. And I know the battery is crapped out won't hold a charge but all my other quad will still run normal with no battery on it?? Why won't this one?

 

Does this model have a fuel pump by chance? The high idle then stall is a sure sign you are not getting fuel to the engine.

 

Got it fixed guys just threw a battery on it had to make my wiring a little long cause isn't the proper battery and strapped it on the back but she runs like a new one went on a good 2 hour ride not one problem. Weird how it had to have the battery tho still don't get that

 

Thanks for the help guys this site will come in handy when I go buy another crappy quad and can't get it going haha

 

Depends on where the spark comes from...some just need the connection to be made (my Polaris scrambler can run on a dead battery, but does need that loop closed), others rely on the battery for the spark...many cars require a good battery to run...really depends on the wiring...


Electronics can be the toughest to diagnose...too many damn safety switches/grounds/stator/CDI/rectifier/fuses...and on and on...