BLDun

I have a '76 with a refurbished 350 running 305 hp. I have a Holley 4175 650 cfm on it. I have had some problems with the Holley over the years and have attempted to rebuild it myself but it never quite worked the way it should have.

So I sent it out to be completely rebuilt and got it back a few days ago. Started right up and runs well so far. Here's the problem: Today I took it out for a test drive and when I had a little space on the road I punched it to the floor and after a few seconds let off. However, the rpm's never returned to where they should have been. The engine continued revving at around 2500 rpms. I finally pulled it over and popped the hood. I could find nothing wrong at all. So I got back in and started it up and the idle had returned to normal.

I was afraid to punch it again for fear it might do the same thing. Got it home and took a look but I can't find anything that looks to be out of order.

Any ideas why it would do this??

DUB

Did you remove your air cleaner when it was revving to 2500 rpm's when you pulled over and stopped??????

If so...it can be that when you took the accelerator linkage to FULL THROTTLE...you carb linkage is binding on the underside of your air cleaner base....but when you took the air cleaner off...or even loosened the wing nut for the air cleaner...it went back to curb idle.

I HAVE encountered this before. And it can simply be that the base of your air cleaner...especially if it is an aftermarket base...is not correctly positioned to allow the throttle linkage to go to full throttle and return.

DUB

BLDun

When I pulled over and stopped I shut it down immediately. I was going to remove the air cleaner but it requires an allan wrench and I didn't have one with me.

It is an aftermarket air cleaner but I haven't had any trouble with clearance before although I will check it to make sure.

Thanks

cardo0

Linkage or spring problem interfering with throttle operation.

BLDun

I pulled the carb today and checked it to make sure the secondaries weren't touching on something causing them to stay open. Nothing I could find. So i reinstalled it and took another ride. Did it again but this time it didn't stayed revved as long. When I got it back home I checked some more and found that the spring wasn't strong enough to completely return the throttle to the idle position. So I shortened the spring and now it seems to work just fine. I'll keep my eye on it and let you know if I have any more problems. Thanks for your input.