I have been having nothing but problems with this @#&*! thing :rant: I have been fighting a rich condition when cold for quite some time :rant: I have tried EVERYTHING to correct it, to no avail!! :rant: I would happily trade this ^&%$$# thing for a good working 850 double pumper
my problems have been since new,the claim of " street ready out of the box", "bolt it on and go", are sure wrong! I have blown 3 power valves,(supposedly million mile blowout protection). I have tried numerous tuning tips, ideas, and it STILL acts like crap! :rant: :rant: there may be people out there that have had success with these carbs, but I sure have not!!! as I said, I will GLADLY trade it for a good 'ol 850 double pumper!!
somehow, I was afraid of that oh well, it's tucked away in the garage for the winter, will deal with it when it warms up
Problem occurs just after starting the engine? Have you tried adjusting the choke pull-off piston so it opens the choke blade a touch more? That'd be the first thing I'd be looking at. Problem occurs for the first few miles? Lean out the choke coil, and verify proper voltage to the choke heater. Verify the choke heater works by measuring resistance through the terminals with an ohmmeter.
I have not adjusted the choke pull off piston, how does one do that?? I did see a little piston in the housing, when I had the heater out for inspection. there's no vacuum fitting for it on this model (I have another housing off an older 600 that does have a fitting) heater element does work, I tested it on the car, with key on the choke plate opened normally. this always occurs during the first 5 min of running. choke is leaned out now, about 2 or 3 notches.
Have you tried to call/write the people who made this type carb for some technical help? Carb problems are usually fixed with some minor adjustments but it helps if you know which one to try and how to perform them. Most carb manufactures have a toll free number to call for technical assistance. You may have a good carb with alittle help in tuning.
yes I tried that already, not much help and.... by the way.... before any one mentions it.... I'm not switching things over,and run a Q jet. there's got to be an answer here, to make it work like it should
Holley has the instructions for adjusting the pulloff piston extremely well hidden on their web site. There was a time I could find it, but I just looked and had no luck. It is NOT included in the instructions for the choke conversion kit (!!!) and it is not included in the instructions that come with a complete carb. Last time I found it it was as an illustration included with the instructions that come with the rebuild kit for a carb. And I can't find it now. At any rate, I think you need a special tool (paper clip, with the end of the wire bent at a 90 degree angle about an eighth of an inch long) which fits into a hole in the choke housing bore for the piston. Then you hold the piston retracted and measure the gap between the top of the choke blade and the air horn. Adjustment is done by (slightly) bending the linkage rod to the choke blade. Point is, you'd bend the linkage to very slightly open the choke blade when the vehicle starts. The vacuum supply for the choke piston can be either INTERNAL or EXTERNAL. The internal supply is done through drilled holes in the main body casting, and drilled passages in the choke housing. The choke housing passage is sealed to the main body passage using the stupidist tiny gasket you've ever seen. Most of 'em are about 1/4 inch square, with a tiny hole in the middle. Half the time they fall out before you get the choke housing secured to the main body. The external style is much easier--there's a short hose from the choke housing to the front of the carb. Problem is, it's a special hose that's bigger on the carb end than on the choke housing end. If you don't have the hose--you've got the internal vacuum system.
once I do this adjustment, it will open as soon as it fires? right now, it goes completely shut as it cools down. takes about 2 minutes or so before it begins to open. thanks for the info!!
HAH! FOUND IT. This is a link to a 4-page PDF document on the Holley web site. You're looking for Illustration 15 on page 4. Note that this is the PROCEDURE, but it does not list the actual specified distance from choke blade to air horn. I don't know where to find that. All I can say is check the adjustment, and if the engine gargles on gasoline or seems to be rich--open the choke blade another 1/32 or so and see what happens. Open it more if you need to. http://holley.com/data/Products/Technical/199R8339.pdf
Yes, the choke will COMPLETELY shut when the engine is cold. The choke should pop open "about" a quarter-inch as soon as the engine is running. That's what this adjustment is for--you're fine-tuning this initial opening. Once the choke has opened this little bit, the engine should run nice and smooth--at fast idle until you touch the gas pedal, and then at medium-fast idle--and as you drive the car, the electric heater warms the choke coil, the choke will gradually move to full open, and "normal" idle speed. So yeah, there's a bunch of stuff going on in the choke system, and it's all interrelated with the fast idle cam 'n' screw, the pulloff piston, the unloader linkage, etc. But lets start with the pulloff piston. I kinda expect that once you get the pulloff piston adjustment correct, you'll need to richen the choke coil adjustment pretty close to the center "index" position. But you won't know for sure 'til you do the pulloff adjustment first.
If you want a carb you can just bolt on and drive, why are you messing with a holley brand? Wise up and purchase a Edelbrock. not much tuning involved. I've got 4 holley's laying around from 650 to 750 doubles. Why use them when I can pull my 750 edelbrock of my chebby and use it my my 455 in replace holley. I find that they idle great, easy air fuel adjustment, and easy to change metering rods if need be. All while bolted to motor.
The eldebroke carb will not be sufficiant to handle the engine in Jeff's car. A 800 cfm Qjet would be better than that.... He really needs to save his money and put a Demon carb on. With about 900 cfm that would be MUCH better and they actually do come out of the box and idle. (been there done that)
