When I start up my truck it sounds like it does when the tank is almost empty. It climbs in rpms for awhile and then drops back down to normal idle. When I give it WOT and then go back to idle it does the same thing . Afther about a minute it runs normal. Any ideas?

sounds like you got an air leak i would say seal the opening were the carb going and the back plate and see what happens i had the same thing with mine did that and idles great

from the tuning bible...........


It is possible to set the idle screw adjustment in to far but yet the idle speed is not high. Even though the air regulation [carb barrel or slide] may be set to a position that would normally equal a vary fast idle, the idle is low because the low speed mixture adjustment is set so rich that the engine loads up with excess fuel and the engine goes into what’s commonly called a four cycle idle.


One tell tail sign of this is if after reving up the completely warmed up engine it tends to idle fast for a few seconds then drops to lower idle speed. If you start leaning the bottom end a little at a time [then repeat the reving up and idle test] and it takes longer before the idle drops your going in the right direction.


what engine do you have?

This sounds to be on the right track. Video always helps when trying to assist on the internet.

I have the original engine that came with the lst. I just bought it and it has less than a gallon on it. I broke it according to the manual.

The engine only does this for about a minute after starting it when it is cold. It could be an air leak.

Ill try and get a video up in a day or so.