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Posted

i have a 2011 hisun ys 400  idles high,once in awhile, runs horrible under load. iv'e put several differant carbs on it , cleaned the gas tank , took off the vaccum fuel pump and put  an 

electric fuel pump.  no change HELP 

this is a carburated engine, but was wondering is there any electrical components that meter the fuel flow,  like  mass air flow senser or something like that could be causing the fuel delivery

problem.

ps i have owned this rig since it was new , and haven't had a full  year of flawless riding.

 

oh and bought it from menards and told me i was stuck with it.

  • Alex changed the title to Yardsport ys 400
  • 2 years later...
Posted

I have the same one (Menards' Yardsport 400). Mine has been running great for years. Put it up in the shed for the winter. Spring comes and it won't start. I figured it was probably stale gas (sat for 6 months) although I had been doing this every year previously with no problem. So, just in case, Drained the gas & refilled with fresh; pulled the plug > good compression; good spark. Cranks fine. Pulled the air filter element > clean. Sprayed starter fluid into the filter housing > still not a pop.
Fuel filter looks dry. Does it get "filled" after starting or ?  I'm gonna set up a fuel container on the roll bar so it provides gravity fuel pressure and try that. Anyone have other suggestions?

  • 2 months later...
Posted

OK, I put a PLASTIC container up on the roll bar with duct tape and filled it with gas. Put a nozzle from my aquarium supplies in the bottom. Ran a hose directly to the carb, bypassing the fuel pump and fuel filter. With gravity as the "pump" I tried to start it and it caught and ran after 2 cranks! I visually verified that the fuel pump was pumping (spurting gas out) and caught the gas in a container. I let it warm up a bit, shut it off, and put everything back as it should be. It then started right up (and has several times over a week, since)! So it's back to normal and I have no idea why it wouldn't start.

Posted
2 hours ago, Joe Breaux said:

Stuck float or trash blocking line?

I'm gonna say that a "stuck float" is the best possible answer. The pressure from the gravity feed was likely enough to push open the float valve.

  • Like 1

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