blaster revving wide open

[fastboarder]

so yesterday my little brother was riding his blaster and when he would stop and let it sit it would rev up higher than normal then today he was looking at it and it revved wide open and sat there for like 4 minutes then my dad pulled the spark plug cap cause he took the key out and hit the kill switch off and it kept going then he shut the gas off and it stopped any ideas what could of happened. it all stock nothing done to it

[RideRaceLive93]

well for starter you def have an electrical prob check all the connection check the cdi i bet that what it is clean the carb it may also be running lean casuing it to rev higher at idle but i highly douwt that i bets its the cdi swap it out and check

[woodsracer144]

could also be a base gasket! i had one of them go out...

[sinisterex]

base gasket.

[vondeister]

It has a air leak, mine did the same thing. My air leak was around the reed plate. what happens is they get hot (lean) and a piece of carbon will turn into a glow plug and it will run on with no electrical. we had the key out, switch off and teather pulled.
next time to shut it off, just hop on pull the brake in and pop the clutch in 2nd gear; that will kill it.

you might want to look at the top end / lower end now after the long wide open no load period you experinced.

[vondeister]

blaster piston 2 weeks after the air leak.

[mpblaster287]

I had a blaster that would rev wide open after letting it cool down after riding. The kid that had it before me routed the throttle cable over the pipe so it would melt the plastic casing around the throttle cable and then when it would cool it would hold the cable wide open. Its stupid but it was the last thing i checked.