brad.arcova
Member
Long story short. I have a Holley 4150, 670 cfm, street avenger with vacuum secondaries. I run it on a 383 with a 234/244 cam and idle vacuum is, as expected, kind of low at 13-14 in. I rebuilt the carb about a year ago with a Holley rebuild kit. I have holes drilled in both the primary and secondary throttle plates to get enough air flow through the carb without having too much of the transition slots exposed at idle. Stock power valve is a 6.5 but I put in an 8.5 about 3 months ago because, from reading the plugs (with help from Grumpy), I was running lean at power. New power valve gave very noticable performance improvement and a new plug reading showed that at power I'm running normal to rich.
Just this weekend I pulled off the secondary fuel bowl to replace the jets. The fuel was really, really old. Primary fuel is very fresh. The car was driven over 1000 miles since January, 300 over the prior week. When I rebuilt the carb, before drilling the throttle plates I noticed the same thing, old fuel in the secondary bowl. When I rebuilt the carb, I was careful to blow out the passages on the metering block and the main body with compressed air.
I don't push my engine much (1500-2500 rpm normal driving, occasional 2500-3500 accelerating through the gears) so I don't really expect to be operating on the secondaries very much.
On the other hand, I'd expect to see enough fuel flow through the secondary idle circuit to at least keep the fuel fresh. Is this normal? Since I've rebuilt the carb once and blown out the passages and don't really know what else to do. I could replace the vacuum secondary spring but that would only make a difference under higher acceleration/load.
Advice appreciated.
Brad
Just this weekend I pulled off the secondary fuel bowl to replace the jets. The fuel was really, really old. Primary fuel is very fresh. The car was driven over 1000 miles since January, 300 over the prior week. When I rebuilt the carb, before drilling the throttle plates I noticed the same thing, old fuel in the secondary bowl. When I rebuilt the carb, I was careful to blow out the passages on the metering block and the main body with compressed air.
I don't push my engine much (1500-2500 rpm normal driving, occasional 2500-3500 accelerating through the gears) so I don't really expect to be operating on the secondaries very much.
On the other hand, I'd expect to see enough fuel flow through the secondary idle circuit to at least keep the fuel fresh. Is this normal? Since I've rebuilt the carb once and blown out the passages and don't really know what else to do. I could replace the vacuum secondary spring but that would only make a difference under higher acceleration/load.
Advice appreciated.
Brad