We've been having a problem lately with my sons viper 70. The slide inside the carb doesnt open at all on it's own. If I lift it with a screewdriver the motor will rev up ok but otherwise it runs slowly and quickly dies. I tore the carb apart to clean it and decided I'd go ahead and just do a full new carb kit including new slide. I still have the same problem after putting it all together again. Any advice is appreciated.

 

Welcome to the forums.
The slide not raising eh..
Going on what you reported::
First thing I think of is the throttle cable not moving correct (needs lube or new) or maybe the cable adjustment, or maybe there is a problem at the thumb throttle.
Let's go fronm there.
Maybe others will chime in.

 

Thanks LT80. The slide is not operated by a cable though. The throttle cable connects on the side of the carb and it does open the butterfly properly. It appears the slide should be opening by a vacumn somehow. The diagrapm is new, no tears.

 

Sorry, Not that familiar with the 4 strokes
My rancher has the same workings as yours. It seemed on mine that it raised with the engine rpm's. I agree, it would seem to be operated by vaccum...

Would you happen to be from Ireland?