Idle rpm?

Sounds like something is putting tension on the throttle cable.  Try just disconnecting it while the car is running and see if that changes anything.

Lane, I have a bit of slack in the accelerator pedal cable at idle as it is, not much just a little. It just seems to me that the carb throttle return springs are weak and not returning the throttle arms to full detent?

I've been considering using some heavier springs that I have lying around that were used for V-8's? They are stouter than the wimpy springs on there now...

Once the engine is up to temp, disconnect the throttle cabel....  If the engine still idles high you have a bind in the linkage connecting the carbs..(this is not all that uncommon)    If the engines idles as it should, look for the "reason" as something is probably dragging on, or binding the cable....  Try to keep the return springs as light as possible.....  Too heavy and it becomes "WORK" to drive the car.....   Make sure there is a tube through the fan shroud for the cable to travel in.....  I've seen a new install where the tube was omitted, the cable tried to saw through the shroud and locked the throttle almost wide open in the heart of Charleston S.C.

Not a fun event....     

Leon, My accelerator cable runs through a tube through the shroud, disconnected it operates smoothly...connected it operates smoothly, no binding that I can see or feel...

I know heavier throttle springs will cause more accelerator pedal tension from using them on V-8's. On a  built V-8 it's sort of a given...especially if your are trying to get the idle down some.

You stated earlier that you could pull up on the carb linkage arms and reduce the idle speed....   If you can do this with the cable disconnected, you might want to disconnect the carburetor arm linkage and see if the problem gets better....   Worn pivot points and other things can cause binding.....  Some times you just have to set things up from Ground Zero to get it right....

The one I chased for three days turned out to be mismatched  throttle shaft actuator levers....  This was on a set of Dels, but stranger things have occured with Webers...

...also, my 2cents, and you all know that I know what I am talking about as it has been said that when Rusty Smith talks people listen... or maybe that was a commercial.

...anyway - 44idf's come stock with 36 venturi's - with a 1915 wouldn't you want to run something a bit smaller like 32 venturi's? This may help with the hesitation. The high idle is a slam dunk and can be corrected with heavier springs like you said.

Edit - almost forgot - my engine idles at 500 rpms. It may have Bradycardia though. The carbs were rebuilt last year too.

Rusty, the venturi's are 32's same thing I changed the 48 IDA's out to in the Cobra for this alititude.

Leon, that is what I'm afraid of that I'll have to go back to 'ground zero'...grrr!

So what's the big deal here?

Throw a new pair of springs, or slightly bigger springs, on and get on with it.

They'll probably work just fine.

If you have the CB Performance linkage take a look at the balls that go against the ends of the springs that are in the ends of the hex bar.  I went crazy trying to figure out my idle issue---same as yours I think. It would idle right about 10% of the time and would be 1,200-1,300 rather than the normal 900 RPM.  I could move the linkage with my hand to make it idle correctly (Gordon and a few others will verify what a PITA I was running this down.) The left side ball was worn almost all away---hard to see in the photo but the worn part os on the left and the one on the right is new.the linkage was binding and at idle the synch was always off.  Also the heim joints were stiff as hell and added to the binding. I replaced the entire linkage and now it is swwweet. 

Trust that grumpy old guy in black glasses w/ the walker.

Gordon and all, I replaced both throttle return springs with the lightweight ones from a 4bbl throttle return kit, I have several sets of used springs in my 'junk' drawer, you know the drawer where you put  " I think I'll keep this it may come in handy someday" stuff...LOL.

That did the trick it now comes to idle at just a little under 900rpm. Accelerator tension is a bit tighter/firmer but not that noticeable. The engine wraps up and comes back to idle just fine now and it stays there and doesn't creep up or down.

Thanks for the advice everyone.

Gary

On my CB linkage, the hexbar was the part that wore down. The ball links still looked new. I bought actual heim joints, and replaced the CB ball ends. JB Welded a 5/16" rod in the hexbar, and added some small springs. Cut the ear off the air filter base, drilled a hole, and installed heim. That was after only 3K miles. Now I'm at 35K and it's all good. No more idle woes, smooth as butter and stays in sync.

Heim joint conversion on the hex bar ends is the way to go, as many here can attest.  I think Gordon invented this, or at least perfected it, or maybe just commercialized it -- thanks Five Cent Racing!

Shown is a pic of the kit from somebody (Gordon??), and as I applied it to my car w/ Gordon's kit.

Gary,  Congrats on a good fix.  Wish they were all that simple.  Hope you do not have too much tension now, as this side force, if excessive, can lead to faster-than-normal wear of the throttle plate shaft to carb body bearing.

I believe that's Gordon's Heim kit for the Type 1.  I have one of his kits here but was unable to use it because the configuration of my Type IV wasn't compatable.  I'll be fine and I got 40,000 miles out of my first CB Performance hex bar set up so I expect the new set up to last at least as long. Still I wiah I had been able to use the kit Gordon sent me.

Gordon's kit is top quality with aircraft quality heims that work as smooth as  buttah.   The picture Danny posted is exactly what the instructions show in five cent racing's kit and you can see how it looks mounted.  Great upgrade from the CB Performance linkage.

I am going to donate the Type I Heim joint kit for the raffle at Carlisle.  Wish I coukld have used it.

Gary:

I don't have return springs on either carburetor, choosing, instead, to have a single return spring for the linkage train that pushes the linkage to zero, rather than something that pulls the carb actuators shut.  It is installed around the throttle cable, centered on the shroud by the cable tube that goes through the shroud, thereby pushing on both the fan shroud and then against the actuator (center) arm of the linkage by using a simple cap plug as an end for the spring to fit around and finish it off nicely.  Tension value was found by trial-and-error.

It looks like this, and works great for 15 years:

Gordon: That is BRILLIANT!!  Pls send me one of those springs  -- 

Gordon, great setup! Probably helps in keeping the carbs in synch?

El Frazoo, maybe others had done it before, but I had the original idea(and exactly the same time as Mark with another Spyder, 3000 miles away). I had it on my car in 2006 or 2007 when I first stared coming to Carlisle. Then WB did it, then Gordon IIRC.

Kelly, go to the hardware store and look......

Sorry, Danny......But that's the only return spring Pearl has ever had since 1998.

Great minds tend to follow "the Force", though, don't they?

Kelly:  That spring, and all of its' cousins, are available at ACE Hardware.

Not talking about the spring, my friend. I was talking about the heim joint fix.

The original thread that details it all is gone and no longer in Spyderclub's archives. That happened when they changed the forum software years ago, some stuff transferred, some did not. This was the thread from 2006, but it's dead:http://ww.w.spyderclub.com/vie....php?f=19&t=8416

This was the summer after Carlisle 2006, so I had it done before 2007.

Oh....THAT!

Yeah, I stole the idea from Danny....That's absolutely true.

All I did was to source all of the parts needed and put them into a handy-dandy kit to make the conversion a wee bit easier.

And the last time I bought the Heim joints (for the set I sent to Jack Crosby), the bearings I used to get had been superseded by another P/N at a 30% increase!  German versions are NLA, nor are the Swedish ones, but I found some really nice USA parts for Jack's kit.  I haven't made up any new kits since, though.

It really DOES work, for a lot of us. Kudos for getting it out to some of our brethren, Gordon!

Maybe you should make up a special throttle return spring for Frazoo. Shrink wrap it on some cardboard like the old rubber band VW repair kit!

... and sell it to me at 200% mark-up.

Gordon, I really wasn't asking you to ACTUALLY send me one of those throttle cable springs.  My local HW store has a grand box of springs of all shapes and sizes.  So yes I could go get me one of my own.  You mentioned trial and error to get the pressure right, so I wonder how strong that spring is -- I can sorta see by the pic how long it is.  This would definitely put the cabash on wearing out the throttle/carb bearing.   Like the man said: learn something new here just about every day.