I have a 1985 Ford F-250 4x4 w/ a 460 and a Holley 4180C 4-barrel carb on top. I've owned this truck for about a year and a half, and it appears the vacuum secondaries have not been opening on the carb.
The truck was very low on power when I bought it-- I did a full tune-up and rebuilt the carb with a geniune Motorcraft rebuild kit. It's the first carb I've ever rebuilt (I'm far more competent in working on fuel injected vehicles), but despite that, I didn't encounter any real difficulty; it was pretty straightforward.
The engine perked up, but I noticed it still runs out of breath around 3k RPM. I also noticed the secondary throttle plates were accumulating varnish, an indicator that they weren't receiving any fuel that would otherwise keep them clean. As a test, I tied the primary & secondary butterflies together, much like mechanical secondaries (except they open simultaneously, not sequentially). At WOT, the difference in power is night and day. The engine pulls like a mule clear to 4,500 RPM and makes wonderful noises that only a big block V8 can make, that weren't present before.
Something is amiss here and I'm looking for suggestions / input on where I should look first, what things I can try to fix this. Thanks in advance!
The truck was very low on power when I bought it-- I did a full tune-up and rebuilt the carb with a geniune Motorcraft rebuild kit. It's the first carb I've ever rebuilt (I'm far more competent in working on fuel injected vehicles), but despite that, I didn't encounter any real difficulty; it was pretty straightforward.
The engine perked up, but I noticed it still runs out of breath around 3k RPM. I also noticed the secondary throttle plates were accumulating varnish, an indicator that they weren't receiving any fuel that would otherwise keep them clean. As a test, I tied the primary & secondary butterflies together, much like mechanical secondaries (except they open simultaneously, not sequentially). At WOT, the difference in power is night and day. The engine pulls like a mule clear to 4,500 RPM and makes wonderful noises that only a big block V8 can make, that weren't present before.
Something is amiss here and I'm looking for suggestions / input on where I should look first, what things I can try to fix this. Thanks in advance!