Chevy Vortec / 5.7, idling down issue

[NFA]

Hey everyone, I have a Chevy Vortec 5.7 with a jet pump on a 21' Thunderjet. Engine fires and runs great. My problem is sometimes the engine doesn't idle down all the way. Regular idle is around 700-800RPM , but sometimes it'll stay around 1000-1100RPM. I have to open it up again and run around for a minute or so at WOT and then bring it down to idle and hope it drops to normal idle RPM.

This doesn't happen all the time, but enough to make me a little concerned.

Any ideas on what it could be? A sensor, throttle cable? Anything?

Thanks in advance.

 

[Scott Danforth]

check your throttle cable

 

[Bondo]

Ayuh,.... Like Scott says, check the throttle cable,....

Boats don't use throttle return springs,.. the cable has to push/ pull a slight tension against the throttle stop/ idle screw,....
If there's Any play, adjust with 1/2 turns, til there's a tiny bit of pressure against the idle screw,...