Chased a flutter that could be heard in exhaust sound to find a few weld leaks in exhaust system that I fixed. Problem seemed to go away but when I rev the car from idle the flutter sound comes back!

So, I start the car, let it warm up via elec choke, tap gas pedal to release choke and car exhaust is CRISP and nice! I give the car a quick rev-up (2000 Rpm) and when it goes down to idle the annoying flutter comes back (idle rpm stays the same). Drive the car and sometimes it's there and sometimes isn't!

I've adjusted carb, pulled adjusting screws out and blew ithe circuits out with carb cleaner. Idle drops when adjusting left and right banks...

440 with less than 1k miles, Eddy 750, rebuilt back to stock specs...

Thanks

Steve

Define the flutter more specific. Is it like a momentary miss where the rpm drops slightly for a split second? Put a vacuum gauge on a manifold vacuum port & see if it drops when it flutters. always done this since built? Non saying it's the carb but the eddy 750's (1407) have had alot of reported problems

Does your passenger side exhaust manifold still have a functioning heat riser assembly?

The sound is like a dry raspy humm that has no break. It's just a Hummmmmmmmmm... The idle doesn't scavenge or anything. It stays fairly level and vacuum holds steady at around 14 (if I remember correctly...maybe 15).

The factory heat riser is gone. All that's left is the bar that intersects the manifold opening that once held the flap.

Thanks!!

Flowcrapper muffs ??

Yes, but sound good when that flutter isn't there.

Went home for lunch and figured I'd run the engine and look around the engine with a flashlight. I found a small stream of smoke coming from the rear manifold on the passenger side (as the car's exhaust sound was fluttering.) The nut was on there just barely snug and had at least 1/2 turn in it to tighten it down (and checked all the others). It appears the sound has gone away with tightening just this one area! Could it be that small of an issue causing such an annoyance?? I guess it wasn't enough to "tick-tick-tick" from the engine bay but enough to disrupt the flow out the exhaust?

I guess time will tell....Thanks for the help!