Why did the float stick?

Mini Bike & Go-Kart Parts

#1
Riding in the mountains today the float stuck wide open in my unmodified LiFan 212cc 6.5 HP engine. ( same as HF Predator).
Non-alcohol gasoline used. Plastic tank, no rust.
In line filter used ( new)
Carb cleaned and ran fine yesterday for over a mile down a dirt road.
No vacuum problems with tank of lines.
The needle valve was just checked and cleaned last week. It was not dirty.
Needle valve float platform was checked and is at the proper angle.
Float is not cracked/flooded.
No idea as to why this happened. Gasoline fuel line system was not pressurized from heat and is ventilated. ( Gas tank is 1 1/2 gallons and sits on top of the center support frame member. 10 inches above the carb.
When the bike was towed back to the trailer the engine was started up and ran just fine again even after climbing a steep hill and decent with the engine never missing a beat, no gas leaking out the weep hole anymore.
Any ideas as to why the float stuck open dumping fuel out the weep hole and flooding the engine?
 

SAS289

Active Member
#2
That may just end up in the unknown category. And might be just a "one off" problem that may never happen again. Makes you wonder if when it initially happened if you would picked up and bounced the back tire that it may have freed it.

To even try to figure it out you would either have to wait for it to happen again, or take the bowl off and move the float around to see if you can duplicate it and maybe see why it would happen in the first place.
 
#3
There is sometimes enough slop in the pivot pin to float connection ,they can touch the side of the carb body .China carbs seem to have that issue more than the better brands .
 
#4
It did it again today. I took it off and installed a non-adjustable carb version and test ran the engine under load up my mountain. The engine back-fires after a heavy load is backed off.
I ordered a replacement carb that is adjustable.
 

SAT

Well-Known Member
#5
It did it again today. I took it off and installed a non-adjustable carb version and test ran the engine under load up my mountain. The engine back-fires after a heavy load is backed off.
I ordered a replacement carb that is adjustable.
I would check the valve lash and flywheel key as well.
 
#6
when the leaking carb is working,there are no back-fires.
The 2ND carb has a non-adjustable air/fuel mixture screw. A can't adjust it for my 6,800 feet ASL at home. It's way too rich.
 
#7
When stuff like that happens, I put a smidge of Marvel mystery oil in the fuel inlet,, with a dropper, or oiler,, for R/C cars ect.,
to lube the needle & seat,, & then go from there ..
Added,,
How steep of grades are you going up ??
I lived in the Mtn.s of Co. for years....
Could be a thing where the grade & bumps ect. is affecting the needle from closing ,as the float might be catching on the side of the bowl ect.,, like ''bruces'' said.
 
Last edited:
#8
The bike was in my garage and I turned the fuel on. The carb overflowed. I took the carb off and the bowl gasket was new. The needle valve and it seat is clean and the hair spring is intact. It will just not stop leaking out gas for no reason. A cheap as a replacement carb is, it's just not worth trying to repair the carb again.
The mountains where I ride are very steep. No carb on any bike has ever been a problem as there is always enough play in the floats to allow gas into the bowl to be atomized.
 

Top