I'm still mucking about with the new Holley Street Warrior (0-80457S), especially where the choke is concerned. Since this carb doesn't have a pull off, is there any particular tuning tips to keep under advisement?

JamesC

 

It may have a pulloff. Some carbs used a small piston down inside the stat to do that.

 

There's no passage from choke housing to carb.

JamesC

 

Well that rules that out then...

In that case, the only "pulloff" you have, is the asymmetry of the blade. It has more on the side that "vacuum" would be tending to pull down into the throttle bore. You have to balance the adjustment of the stat between the temp that it operates at and the strength that it holds the blade closed. You could drill holes in the other half of the blade near the leading edge to help it out but there's only just so much you can get out of it that way before it loses effectiveness as a choke.

It does look like it has some sort of passage though; right below the screw that's at 11:00 looking at the stat from the pass side. An electric choke needs that, to draw some fresh air in through, to keep the element from burning up.

Is the choke operation unsatisfactory in any particular way?

 

In the pic below note the rear portion of the blade, which is certainly unlike the blade on my previous 4160.

I think the choke duration is getting close. The fast idle, however, has issues with rising RPMs. At 1700, for example, the RPM's will rise to 2500. I reset that this a.m. to 1300 and the rise peaks at 1750. If I try to bump the throttle to bring the RPM's down, the fast idle falls off altogether and I have to feather it a bit until full warmed. Maddening.

JamesC

 

In your other related thread you mention the timing curve and that there's 12 degrees of advance at 1700 RPM. Have you confirmed this?

 

My longtime shop was assigned several jobs this past summer. One was to verify that timing was in accordance to the 350HO Deluxe manual, which I furnished. So in as much as I trust them....

JamesC

 

Any progress?

 

No. I did have a moment to look at the fuel level on the primary bowl yesterday. Appears there's some leak down (I removed that bowl to install the new PV and jets). The car exhibits none of the typical symptoms of a blow PV. Ahh, carbs will be the death of me! I believed a new one would eliminate longstanding issues that I'd experienced with the previous one. Nope.

JamesC

 

A quick question: Did your old carburetor have this same fast idle issue?
If it didn't and the experience is new to the installation, could it be that you've created a vacuum leak somewhere? Carb base gasket perhaps? Or a cap left off of a port?
One other thing comes to mind and that's the port you're using for vacuum advance? Is it the same as before or have you inadvertently hooked up to full manifold vacuum and bringing with it the difficulty in tuning? The behaviour exhibited is similar to what happens when using a full time vacuum port. Revs go up, vacuum goes up and the cycle perpetuates itself. It can be a tuning nightmare.
Just throwing a few thoughts out there...

 

Thanks for the thoughts,

JamesC

 

Hmm. I was hoping for a Eureka moment!

Makes me more suspicious of the timing but seeing as your shop have addressed it (hopefully) there may not be anything to it.
When I get an opportunity I'm going to compare your posted timing curve against some other industry examples. At first glance it appears to be an oddball.

 

Here's the manual. Page 4, which provides ignition info, might be of interest.

https://www.chevrolet.com/content/da...e-19210007.pdf

JamesC