Pretty new to ATV repair. I have been riding for quite some time. I recently acquired a 2007 Rancher and I am having a few issues.

First, the ATV is unable to run without the choke always being on full. Just quits out and stalls.

ATV is having trouble running without the fuel being switched to reserve, even though there is a full tank of fresh gas.

What is causing this?

 

Never found a choke on a 420 where is it? The pick up pipe in the tank must be blocked if it will only run on reserve. The correct way is to remove the tap and blow it out. Quick fix, turn fuel off, remove pipe from tap, slacken filler cap, get ready with an air line up the tap and open tap while blowing with air line.

Treat the fuel pump to a new "tea bag" filter and see if this cures your other problems.

 

My apologies, its the 350cc version.

 

2006 was the last 350 rancher after that it was only the 400 AT Rancher and the 420 EFI in 2007.

 

Sorry little off on my dates as well. Double checked and it is an 06, 350cc. Its a Red Rancher with the stick shift for Neutral, Drive and Reverse with an optional push button shifter.

But in regards to the OP, what can be done to remedy my issues?

 

See if its a fuel tank air venting problem. You can check by riding the ATV without the gas cap.
If it runs normal after that then the tank is not venting.

 

Same instructions as the ones I gave for the 420 except clean the carb out instead of "fit a new filter."