Hi folks, Will be firing up my engine soon with my Osborne Q-Jet. John left the choke in and I believe told me to leave in the choke flapper for more linear air entrance? I will be running a T/A manifold. Was thinking of converting to an electric choke but prolly don't need a choke down here in South Carolina. Will the choke always stay open when it's disconnected or will it have a tendency to flop closed, thus requiring me to "hard wire" the choke in the closed position? Thanks! Best, Ranger Aiken, SC
I would carefully wire it open. Make sure you wire it in a spot that doesn't interfere with anything.
More air rushes down in front of the valve than behind it at high speed. The valve will pull toward the high speed air and richen the a/f mixture. The linkage will have some weight to help hold it open if all of it is still hooked up but I wouldn't trust it. If you wire it open, make sure the wire can't fall into the carb. Some coke thermostats will allow you to jam the linkage from inside the cover. You can also buy a manual cable conversion kit to hang under the dash. Mine is completely stripped and stored away.
Hi folks, Thanks for the replies. Yes, I was just going to strip it off and remove it but I'm pretty sure I heard John Osborn said that leaving it in place helped the linear flow of the incoming air. True? Best, Ranger Aiken, SC
My opinion is that the best way to help control air flow is to have the metal plate that fits the 2 bolts behind the air horn. I ALWAYS save these and use them. The plate stands well above the back of the air horn and stops the chance of fuel pullover at high speed. It can also smooth air turbulance in general. * Verify this by sending an email to Cliff Ruggles or join his forum and get the whole drag tested story on this and other issues. http://cliffshighperformance.com/simplemachinesforum/
That deflector is a must have. electric choke with a choke pull off is the best if u ask me. the pull off holds it nice and tight open.
Folks, Thanks, again. I will indeed start following Ruggles' website. What is the best (only?) kit to convert a '73 Q-jet to electric choke?? John Osborn installed a new front choke pull-off when he rebuilt the carb. Not sure why he didn't install a new rear one, too, but I think they were getting hard (impossible?) to find? Best, Ranger Aiken, SC
Ruggles will most likely convert any qjet carb to electric choke. Send him your carb number for a parts kit and price. Your carb may work fine without a rear vacuum diaphram.
The 73 Buick carb doesn't really need the rear pull off for anything. It is tied to the choke section itself. If you keep it on, just make sure it isn't leaking vacuum. That carb also is a divorced choke, there are some electric choke conversions for the intake, but I haven't heard any good things about them. Cliff sells electric choke conversions for hot air carbs like the 75/76 Buick quadrajets.
Thanks folks, I'm sorry my post wasn't clear about the rear choke pull-off. John Osborne did indeed include one when he rebuilt the carb but he used the original one--replacing the front one w/ a new one. Perhaps he did so since, as you say, the rear pull-off is not really necessary--though it IS important that it not create a vacuum leak, as you said. Best, Ranger Aiken, SC
Ranger, Those pulloffs went out of production here a while back, I have them rebuilt thru Cliff Ruggles. Not sure if they have come back to the market or not yet. While that secondary pulloff was used to open the choke slightly farther after initial start-up, you can actually get away with not using it, and being more aggressive with your primary pull off opening angle. Downside is you can often get a start and stall situation. I do use the secondary pulloff in alum head/iron intake applications. We get to keep the factory choke coil for easy start up, and then I pull it almost all the way open with the secondary pulloff. This is required because alum heads have no heat crossovers to heat the choke coil. I had pretty good luck with that this last year, on the Super Stage motor that I put in a 70 STG 1 frame off we did. And for what it's worth, I have tested many, many Q-jets on the dyno, and we never block the choke open, and one has never closed on us during a pull. JW
