View Full Version : Loss of PRM at WOTsecondaries

08-27-2006, 01:18 PM
"I've lost about 300 rpm at WOT. The engine runs fine and the bottom is clean. The prop is perfect.

I suspect that the secondaries on my Holley 4160 are not opening. I have fully opened the throttle (engine off) and checked that the secondaries are not sticking and free to open.

Without having a bud to run the yot while my head is in the bilge, what else can I look for? Am I right to think that the secondaries are opened purely by vacuum?"

08-28-2006, 07:50 AM
Correct. Here's a suggestion: Buy some Bud. Give some Bud to a "bud" and have him eyeball the secondaries as you run along? Sound good?


09-02-2006, 04:46 PM
"1) Try www.fishtheclassic.net ("")
2) I assume you have a 351. Have you checked the timing with a timing light? You should have 30 deg timing advance at WOT."

09-04-2006, 04:20 PM
I spend a fair amount of time on FTC. The main reason i jumped on the secondary idea is that my last carb got gunked up and the secondaries froze shut. I can usually hear the engine whine a bit as they open. Other than the last 300 rpm it runs fine.

My harmonic balancer is so rusted that timing is at best an educated guess. As I have done nothing to change the ignition and or the distributor I figure that it's a fuel issue. When I get some time to spend in the bilge I'll do some more research. Thanks to all for the info.

09-05-2006, 09:00 PM
slindemann you might want to look at your exhust. I have heard of some of the supertraps getting clogged with rust and the result is a loss of rpms.