Hesitation When Accelerating

[zzmac]

Originally Posted by patrickt

But zzmac if your car has ever run right with this carb then it can run right again. What made you send it in for a rebuild?

From what I remember (I'm getting old) I had a gas a leak at the back of the carb so I had it towed in. It also turned out that a couple of the bolts holding the carb to the manifold were stripped so they fixed that and they rebuilt the carb when they had it off.

[patrickt]

Originally Posted by zzmac

From what I remember (I'm getting old) I had a gas a leak at the back of the carb so I had it towed in. It also turned out that a couple of the bolts holding the carb to the manifold were stripped so they fixed that and they rebuilt the carb when they had it off.

Leaks and stripped bolts don't count, so I pronounce the carb fixable. Zip tie the secondaries closed this weekend, take it for a spin to see if the bog disappears, and report back.

[zzmac]

Originally Posted by patrickt

Leaks and stripped bolts don't count, so I pronounce the carb fixable. Zip tie the secondaries closed this weekend, take it for a spin to see if the bog disappears, and report back.

Will do.

[patrickt]

Now, let me show you what I have on my vacuum secondary shaft that tells me how far my secondaries are opening. Some guys put a paper clip on the plunger that is coming out of the vacuum housing, but I prefer a zip tie. If you look at this picture you will see that the zip tie is fastened around the secondary shaft tight enough so that it holds its position but loose enough that the shaft can easily turn within the tie itself. It's kind of tightened up to a "gentle handshake" level. The shaft will rotate counter-clockwise as viewed from this side when the secondaries open. The zip tie is trimmed so that it can be pushed over to where it is touching the throttle screw. This is the position that tells you the secondaries are closed and have never opened any amount at all. On my pic below, you can see that I snapped this pic after a "lightly spirited" run where the secondaries opened up about half way and the zip tie is pointing up at noon on the clock. When the secondaries have opened fully, the zip tie points to about two o'clock. You can easily test this in your garage by holding your throttle fully open and then manually opening the secondaries fully. The zip tie will then rotate on the shaft and remain pointing at the spot on the clock that tells you how far it went when the secondaries were wide open fully. Yours might be one o'clock, two o'clock or more or less. Just remember that with Holley linkage you have to have the primaries fully open before you can manually open the secondaries -- if you try and force it you'll just bend stuff up. Knowing whether your secondaries are opening, and how much, and when they open, is the first step in getting them to open just right. You want to be able to measure the results of something before you start changing things. And the goal, believe it or not, is to get your secondaries to open fully, as proven by your zip tie pointer, but without you really knowing when they did it. In other words, they open so smoothly and evenly that you couldn't detect it by the "seat of the pants" test. But when you check the zip tie you say "wow, they really did open completely during that graduated WOT run."