My sons Sc 90 will start and run about 10 to 15 seconds than dies and won't start again. I have checked the crankcase to see if it is full of gas and it is not, tried cleaning the carb to make sure the needle isn't stuck open, am at wits end. Junior is going to kill me if I don't get it fixed soon. Any help is greatly appreciated.[img]i/expressions/face-icon-small-confused.gif[/img]

 

My sons did the exact same thing. It was under warranty so I took it in. They said it was a fouled plug. They changed it and it works now. Hope this helps.

 

Air filter and plug are clean?
No kinks in the fuel line?

 

Ya . Just cleaned the air filter and changed the fuel filter. Gonna try to get a new air filter and a new plug. The plug does foul but it has a real good spark. Must be a fuel air mixture problem, my guess is it's tied to that damn electric choke. Thanks for the input.

 

Dude, if the resistor on the plug is black it is fouled. Change the plug, heres a tip when you go to the dealer buy a couple extra plugs in case this happens again. But i bet ya it's the plug[img]i/expressions/face-icon-small-happy.gif[/img]

Keep on riding!!

 

Try loosening the gas cap. It could be a fuel venting problem. My daughters SP90 has a problem just like that if the cap is on air tight. Runs a bit - then quits.

 

Have you washed the unit lately?? Did the problem begin after the wash?? I have a easy fix it that is the issue.

 

Check for kinks in the fuel line by the cutoff switch. just try putting it on reserve and see if it runs ok. My "on" gas line was kinked.

 

Dude, I know the plug is fouled. Just curious as to why it is fouling. No it has not been washed lately. I will check all the fuel and vent lines to be sure they are not kinked. Appreciate all the help. will let you know the outcome.....

 

Here is an easy way to check the fuel issue. Locate the pink fuel drain line on the bottom of the float bowl. If it is missing go to a hobby store and get a piece of line for the small RC cars. Take the fuel line and hold the open end just above the top of the float bowl. With the fuel line being held up, open the bowl drain screw about three turns and watch to see the fuel enter the fuel line. The level of the fuel in the line will be the same as the level of the fuel in the bowl (as long as your fuel petcock is on).

If the fuel level is OK, go ahead and start the engine. Watch to see if the fuel level drops just before the engine dies. If it does, you know you will need to service the fuel delivery system. Start by removing the gas cap and trying the above test again.

If fuel is NOT the issue (I suspect it is fine), get an inductive timing light and connect it to the coil high tension lead. Watch the light as you start the engine. If the light goes out as the engine dies, the problem is in the ignition kill system. (I can help with this issue later.)

If all of the above is OK, move to checking the head gasket. These machines are well known for leaking head gaskets. It will start but run lean seconds later and die. Pull the plastic cylinder cover and inspect the area between the head and cylinder. If you see any attached dirt or oil, your gasket is done. Get a new gasket and properly torque the head.

There you go "DUDE"