Preload problems?

[Belgium Cuda]

I can't get my 340 to run properly under 2000 RPM in neutral, have a AIPGAP inlet and a Eddy RPM cam.
Can wrongly adjusted rockers give this problem? 

[ShelbyDogg]

Probably a vacuum leak under the carb or intake. Is everything tight? How did you adjust your rocker arms?

[Belgium Cuda]

Everything is new except the carb so it shouldn't leak vacuum. I adjusted to zero plus 1/4 turn but exhaust cyl1 lockingnut has another position
then the rest hightwise.

[ShelbyDogg]

Here is a simple rule to follow when adjusting your valves: 

when the exhaust valve starts to open adjust intake valve, when the intake valve starts to close adjust the exhaust valve.

Do it this way, then move on to see if you have other problems.   I said do this first since you think that you may have a valve lash problem. 

If Everything is new, you only have one chance to break in your cam. That will not happen if you are playing with it below 2000 RPM.

Rob

[HP2]

Probably a vacuum leak under the carb or intake.

I'll add to this and say if you have power brakes, the vacuum booster can be a source of leaks as well.

Disconnect any vacuum hoses attached to the carb/intake and block off the hole. See if that helps the idle. If it does, then there is a leak somewhere in that line/device.

[Oldschool]

Get a can of spray carb cleaner and spray around the intake, carb and carb base, power brake booster----any place there could possibly be a vacuum leak.  Do this s-l-o-w-l-y.  Listen for the engine rpm to increase if you spray where there is a vacuum leak.  Pretty easy to isolate the leak using this method.     

[Aussie Challenger]

  All of the above, however check distributor and leads

[Belgium Cuda]

Mounted an old carb and the problem is gone, didn't find any fault on the other one. 

[MEK-Dangerfield]

Mounted an old carb and the problem is gone, didn't find any fault on the other one. 

My guess is maybe it wasn't on tight enough, or possible something is warped?     I learned my lesson and use a little Gaskasinch now when I do a carb swap. Is it possible you had a port unplugged on the carb? Not being able to idle under 2000RPM is a serious leak. 


  Mike

[Chryco Psycho]

do you have enough timing below 2000 ?

[Belgium Cuda]

Well, about the timing I start to doubt myself concerning if I got the distributor/intermediate shaft/timinggears right because
it runs very poor on low RPM's.