Sticky Throttle Issue

return springs big enough?

They were in the past.  When I was manipulating the carb after disconnecting it from the linkage it felt as if something was binding or scraping when I tried to close it that last little bit.

Lane, take a mirror to the backside and check if the linkage bolt is touching any gasket material sticking out. I had this problem and just trimmed it in place. I use no return springs and all returns as it should.

What linkage bolt are you talking about?  Can you provide a picture.  Remember, I use the CSP bell-crank linkage rather than the usual hex-bar type.  Are you speaking of the carb parts themselves?  That would make sense.

The vertical heim rod to carb. Mine was a Hex bar and I'm not sure about the BC. Is this something that just started? You do any tinkering before Carlisle? It might just be set to tight.

Lane Anderson posted:

They were in the past.  When I was manipulating the carb after disconnecting it from the linkage it felt as if something was binding or scraping when I tried to close it that last little bit.

I had the same symptoms on a Weber on an earlier engine and it appeared that the pivot shaft was binding in the carb body for some reason when hot. I took things apart and lightly honed the carb body out, greased everything and all was ok afterwards. 

I've heard of and seen evidence of a butterfly binding in the venturi body too after some years of service. Things get a little worn in the shaft and some thrust goes one way or another and the butterfly would bind. 

Nah, I haven't touched the carbs since Danny Pip tuned 'em at LAST year's gathering.  The linkage has been on there for a while and the carbs sticks even when it is disconnected.  It's in the carb itself somewhere.

David may be on to something.

Sound kinda like what my gut is telling me.  I guess I know what I'll be doing this weekend.

Lane Anderson posted:

Sound kinda like what my gut is telling me.  I guess I know what I'll be doing this weekend.

Sometimes if the shaft is / has shifted a bit with wear, a "thin" washer here or there may set things right. Aircraft  ( AN ) hardware has regular and ( thin ) washers in every US bolt size. If you need a " thin "washer, Lane get straight to a small airport , plead your case and the local AME wrench will give you a few. 

The only problem here is that Stroud's talking about the Weber progressive carb. That is NOT the same as Lane's IDF. IDF carbs have bearings just like the Dell DRLA. The progressive carb does not have a bearing, I believe the throttle shaft runs in the aluminum carb body directly, which is why they wear out so quick and won't hold a steady idle. You see, they wear, then they leak.

But Lane's problem may be some metal flashing or something in the throttle arm, bearing, washer, nut, and whatever the folding washer that locks the nut in place is called. Also, as I said in another thread, it could be one of the butterflies not centered on the throttle shaft just right. The only way to fix that is to buy some new throttle shaft screws BEFORE you monkey with it. You'll pretty much destroy the screws taking them out. It might even be a dry bearing, as Gordon suggested. The only way is to get in there and look at it, or wait until the winter and send the carb to me.

My opinion, something is binding or rubbing when it gets hot. If you look, there will most probably be some shiny spots where the rubbing is happening. And from what I recall, you've had this problem for years, Lane . If it was mine, I would have dealt with this a long time ago, it doesn't seem to be fixing itself!

"...it doesn't seem to be fixing itself!"

Actually it did - sort of. The CSP linkage appeared to fix it.  I've had no problem with sticky throttle for several years, but now it's back.  Tropical storm Bonnie died a quick death so I'll be tinkering on it today.

Ok, the nuts on the ends of the throttle shaft appeared to be a bit too tight.  Even cold the idle stop wasn't seating against the idle speed screw.  After loosening the nuts it seems to work properly.  I'll take it for a test drive later, assuming Bonnie doesn't come back to life.  It's cloudy, but not raining.  The air outside is awfully "juicy", though.

Problem seems to be solved.  Just did a lengthy blast while driving with some enthusiasm.  We'll see how it holds up.

Now to fix the windshield...

What happened to the windshield? I need to replace mine too.

Dunno.  I got in the car one morning and I'd had a crack from the top almost to the bottom right between my eyes.  I'm guessing I accidentally leaned on it when pulling out my bag the night before.  Luckily Carey knew us well enough to bring a couple.

Bummer.

Yeah, that's definitely a Bummer, but look how well Carey knows us all now......

Must have been a bit of an adventure getting it home intact in your Speedster.

It was...  less than fun, at least on the final leg.