LO206 Sputters off Turn

M

MikeC

New member
Thought this was a common problem but I don't see any posts. 206 (on asphalt road course) makes 4-5 laps fine, then starts cutting out coming off turns. I've adjusted float several times. Getting some oil out of pump vent. Using 15 oz Amsoil 4T. Getting some fuel in overflow.
 
Oil out of the fuel pump vent has nothing to do with your problem, or any other problem other than having to clean up the oil. Clean the vent up with parts/brake cleaner and seal the vent with silicone.Vent is not necessary, trust me.
Before you start pulling carbs apart, check the wire from the coil to the kill switch. It is very common to find it improperly installed when new and gets pinched/cut by engine shroud sheet metal. This usually shows up in corners when chassis is twisting.
 
Disconnect the kill switch wire AT THE COIL and see if the problem goes away. I have also seen a few that rub on the back of the flywheel.
 
We have seen in a few cases that we had to adjust the float height at .900 to fix the sputter problem, you might try that.

Steve
 
I am thinking along the same lines as Steve - raise the floats. I think that'll be the fix.

Another thing to consider...is how the carb is vented - I've seen guys that ran the carb overflow to the same catch can as the oil breather that didn't vent well enough, and it pressurized the carb bowl. Also check that the overflow is not kinked/pinched; not allowing it to drain excess fuel.


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Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cuts
www.CarlsonMotorsports.com
26 years of service to the karting industry
765-339-4407
bcarlson@CarlsonMotorsports.com
 
Just because you set the float level doesn't always mean that you have the proper amount of fuel in the bowl.
There are variables in everything.
Example:
All seats are not installed at the same height in the carb
All needles do not have the same spring strength
All fuels do not have the exact same specific gravity
Even though you set the float properly, once in a while you need to tailor your adjustment.
Measuring how much fuel is in the bowl will often help solve a problem.
You can do this by carefully taking the bowl off (not spilling any fuel is a challenge)
Then measure with a small ruler.
Or you can use a graduated cylinder and measure how much comes out of the drain hose.
 
Great Advice

These are great suggestions. I'll try each one at a time next week, our first race of the season. Just curious though, I don't know any of our group who have plugged the vent on the fuel pump. I saw that in another post and wandered about it.
 
MikeC said:
Just curious though, I don't know any of our group who have plugged the vent on the fuel pump. I saw that in another post and wandered about it.
Click to expand...

Even Briggs allows / recommends plugging the top brass vent ............ see below Briggs 2015 LO206 spec

15. Fuel Pump
Only fuel pump, B&S part number 808656 is legal for
competition. This fuel pump can be identified by both the part
number and Briggs and Stratton Diamond logo on the pump
face. All other pumps are prohibited.
It is prohibited to pulse from the intake manifold.
Relocation of the fuel pump is legal as long as it is spaced to less than 3/4 inch
off of the control plate, B&S #555699, in a similar location that is both safe and
secure. Measurement is from the base of the control plate to the bottom of the
pump flange. Vertical mounting of the fuel pump is NOT allowed. The fuel pump
must be pulsed from a pulse fitting mounted on the oil fill fitting located on the
engine side cover. Aftermarket one-piece filler/pulse fittings such as shown on
the right are permitted. The use of silicone sealant on the brass vent is
permitted. A fuel pump return line to the fuel tank is prohibited.
 
Check to be sure the valve cover/breather is not restricted in any way and your catch tank is vented properly.Either one of those can cause excess crankcase pressure and oil at the pump.
 
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