G9 sputters/back fires

[davekayse62]

ive been battling this problem for a while now, the cart sputters and back fires and it has no power, then all of a sudden it will snap out of it and run great for a bit but eventually it starts acting up again. if you ever had your air filter get oil soaked from the breather it kinda feels similar. im almost positive that it is a carb problem

things that I have done:

thoroughly check all of the wiring
cleaned the carb and jets thoroughly multiple times and its clean every time.
the air filter is clean and dry
new plug

engine is all stock including the intake assembly, im at the point now that im about to order up a new carb, maybe its simply worn out?

also because I had the carb off so many times, I need a new carb/intake plastic spacer . does any one make one that is not a POS?

[1989Marathon]

Does it run bad, then clear up, then run bad while you are driving it, or is it during different rides?

[davekayse62]

it will run bad at start up. then at times it will clear up but it mainly runs crappy the whole time.

the weird part about it is that when it starts to run good it happens so fast, almost like a flick of a switch.

[1989Marathon]

Have you monitored the battery voltage while driving? Maybe check for loose/corroded motor ground. If you decide to check the voltage while driving, put the negative lead on the motor case, and the positive on the battery.

[davekayse62]

Originally Posted by 1989Marathon

Have you monitored the battery voltage while driving? Maybe check for loose/corroded motor ground. If you decide to check the voltage while driving, put the negative lead on the motor case, and the positive on the battery.

ill check that with my meter tomorrow. thanks

[Mike Mac]

I would also be making sure the air box is sealing good. Then look at clutch movement, (greasing and maint). Torque cable etc, just general maint.

[sho305]

Originally Posted by 1989Marathon

Have you monitored the battery voltage while driving? Maybe check for loose/corroded motor ground. If you decide to check the voltage while driving, put the negative lead on the motor case, and the positive on the battery.

Important point; yamaha use wires for all the grounds and they do have corrosion issues. They are not like a car with frame ground the frame is not used. Remember the engine is not on the frame its on the cradle. Carefully check all the cables and connecitons, fuses, plugs, etc. and especially the ground wires.

Could also be the ignitor, the ignition box on the fuel tank. Try pushing the plug in or gently squeezing it or cooling it. Unfortunately that is an expensive part that does not fail very often, most other things can be fixed cheaply.

If you think a fuel issue make sure the tank is vented unscrew the cap and test it, make sure the fuel spurts out the fuel line at carb when you turn it over. Also make sure you have no cracks or pinholes in the fuel or pulse line to the pump, cracks in the lines are known issues they can be replaced with automotive fuel line its not a bad idea if they look bad.

[CAMPERCART2013]

Originally Posted by davekayse62

ive been battling this problem for a while now, the cart sputters and back fires and it has no power, then all of a sudden it will snap out of it and run great for a bit but eventually it starts acting up again. if you ever had your air filter get oil soaked from the breather it kinda feels similar. im almost positive that it is a carb problem

things that I have done:

thoroughly check all of the wiring
cleaned the carb and jets thoroughly multiple times and its clean every time.
the air filter is clean and dry
new plug

engine is all stock including the intake assembly, im at the point now that im about to order up a new carb, maybe its simply worn out?

also because I had the carb off so many times, I need a new carb/intake plastic spacer . does any one make one that is not a POS?

I have a 94 G9 Get a spark tester $5-10 at part store if you don't have one. I just went through this same thing it was like it was fouling the plug then it would take off and run great. if you can get or borrow a used cdi/ignitor to try I would recommend it. I replaced air filter all fuel lines if you replace lines get see thru blue lines like for snowmobile then you can eliminate fuel from the equation...added a fuel filter rebuilt the fuel pump rebuilt the carb replaced the coil and plug cap and it was the ignitor I worked on this all winter. get a spark tester that plugs inline with plug so you can run it then when it goofs up you WILL see the difference in the spark tester if it is the ignitor. I have a video but cant figure how to load it very weah spark most of the time then when it comes to life wow what a difference light freaks out... good luck and let me know if I can help

[CAMPERCART2013]

Originally Posted by davekayse62

it will run bad at start up. then at times it will clear up but it mainly runs crappy the whole time.

the weird part about it is that when it starts to run good it happens so fast, almost like a flick of a switch.

this is exactly what mine did bog bog sputter sputter then whooooa running great then sputter sputter very erratic my guess is ignitor same symptoms I had

[davekayse62]

im going to grab a in line spark tester at sears today