I just bought my son an '02 Scrambler 50 and have a question. Is it normal for the engine to go from idle to approx. 1/4 throttle? It seems as if there is no throttle variation while going slow. I did some troubleshooting (pulled the cover off the thumb throttle) and found that as soon as the throttle switch is released the RPM's go up to about 1/4 throttle - without the throttle cable being moved, then ATV starts moving.

Maybe this is normal, but I don't have another one to compare it to. Otherwise the machine is great.

Thanks!

 

Welcome to the forums.
No, it's not normal. Check to see if the cable is adjusted too tight. Pick up on the cable at the carb. There should be a slight bit of free play.
Revving can be a sign of an air leak. Spray carb cleaner around the carb/reed cage and see if the rpm's change.
Let's go from there.

 

Thanks for the help. I checked the cable adjustment ant it was ok. I assumed since it was idling fine, the idle adjustment was set properly. I was wrong.. after backing off the idle screw it is now working fine. I think the carb needs cleaned, so i'll be getting to that in the near future.

Any idea what the premix ratio should be for these? I would like to remove the oil injection as it doesn't seem to be very consistent (sometimes smokes too much)

Thanks!

 

I run a good synthetic oil at 32:1