620

[PAB]

y does my 620 idle high when i start it up, im guessing its warming up. it also does this when im driving. i was thinking the throttle might be stuck. has anybody had this problem or know what it is?

[moparvwfreak]

yup. my truck does teh same thing. pisses me off ot no end. i know its the carb but i dont know exactly where the problem lies.

[Bugeye]

mine too, but its a vacuum leak at the base of the carb

[moparvwfreak]

so pull the carb and reseal it??? that sounds easy enough.

[lynchfourtwenty]

get some "carb cleaner" and spray the base of your carb and the intake mani where it bolts to the head.. if theres a change in idle theres a leak

[Bugeye]

so pull the carb and reseal it??? that sounds easy enough.

 

gonna do that when I rebuild the carb

[datzenmike]

Check the easy simple stuff first.

 

Check that the choke isn't on slightly. the butterfly plate should be vertical when warmed up. Pull the throttle open slightly and work the choke linkage back and forth looking for tight spots. Make sure the fast idle cam is not engaged. Spray linkage with carb cleaner to clean and loosen it.

 

If fast idle can you push the throttle closed and the idle returns to normal??? the linkage may need adjusting or the idle speed screw needs to be turned in.

 

Check ALL vacuum lines. They are over 25 years old and cracked. Pinch with pliers and see if the idle changes.

[moparvwfreak]

Check the easy simple stuff first.

Check that the choke isn't on slightly. the butterfly plate should be vertical when warmed up. Pull the throttle open slightly and work the choke linkage back and forth looking for tight spots. Make sure the fast idle cam is not engaged. Spray linkage with carb cleaner to clean and loosen it.

 

for mine, the choke is open (manual choke adjusted properly), as far as i can tell the linkages are all nice and free.

 

If fast idle can you push the throttle closed and the idle returns to normal??? the linkage may need adjusting or the idle speed screw needs to be turned in.

 

yes it be closed and the idle returns to normal. i have adjusted the idle ad checked the linkages adn everything sems to be working right.

 

Check ALL vacuum lines. They are over 25 years old and cracked. Pinch with pliers and see if the idle changes.

 

i really should replace them all. also if i just blip the throttle it returns to idle but if i touch it again it jumps back up to 2k quicker than anything. i dont know whats up with it. do you guys think a rebuild would help???

[fisch]

When I put on my weber, the truck started fine and idled fine. As I drove around the idle got higher and higher. And I couldn't kick it down.

 

I finally realized that as the engine got hot the throttle linkage metal expanded and was sticking so that it wouldn't fully return. A very small degree made a big difference to the carb.

 

My solution was a stiff spring from the top of the airfilter cover to the linkage. I think I used a spring from a desk lamp. Solved the issue just like that.

 

I know it is simple as hell, but sometimes on these dattos the simple answer is the answer!