Hey guys, I bought my buddies kids a quad the other day but I cant for the life of me getting to stay running.* Its a 1985 suzuki jr50, its got a new plug and a brand new oem carb.* It runs for about 20 seconds on full throttle then just dies suddenly.* I noticed it has what I think is a fuel pump on the petcock that has two fuel lines coming out of it, one to the carb and the other i have hooked up to a nipple attached to the intake spacer between the carb and motor.* im not sure this is where it goes but the hose just reaches there.* anyway I bought it for his two kids to play around on, he was laid off a few months ago and I thought this might cheer up the kids.* Any help you guys can give would be awesome.* to me it sounds like the bowl fills up and the motors runs until the bowl is empty then dies due to no gas* which leads me to believe its the pump on the petcock thats slowing the fuel down.* I did take it apart and the rubber diaphram look just fine, same with the spring, and all the passages are clear. I could have the lever to the petcock in the wrong position, theres* pri, off and pri, positions not sure which pri position to use.* I hppe someone has worked/owned on of these.* Thanks again,* Dutch

 

A JR50 is a bike.
Anyways, I'd start with a good carb cleaning. Sounds like a jet is getting plugged up.
It sounds like you have a vaccum operated petcock (the tube that goes to the intake).
Apply vaccum and see if the fuel runs. I would try that with the petcock in the off position, then on the prime positions.
Let's start there.