Edelbrock 850 performer RPM Q-jet

[1965C-10]

Hi, my name is Mike, first post here.

I bought and read the Cliff Ruggles Q-jet book often, but thought I would double check here before digging in.

I have a 1965 Chevy truck, shortbed, with a 396 big block (#'s decode to a 1968 pickup 310 HP) and a TH400 trans, 3.73 gears, exhaust manifolds.

I bought a slightly used Edelbrock 1910 850 Performer RPM Q-jet in the original box, with owner's manual for 200 bucks as I had a Carter AFB 600 manual choke on the big block from my old 327.

I have been running this carb on the truck almost a year, but it's running rich I think.

First start of the day (if it has not been sitting for a week) just bump the key, no touching the accelerator pedal, it fires right up just fine, then when I take off the higher idle speed comes into play for about 1/2 mile to a mile.

If I drive somewhere like the grocery store, or anywhere, when I come back to start it, it will take about 5-10 seconds of cranking before firing up without hitting the pedal.

Lately I have been cranking it and if it does not fire right away, I hold the pedal to the floor and it will fire up in about 3-5 seconds.

I'm guessing it's running rich on idle, right?

I adjusted the APT screw to one turn counterclockwise, and it does seem the pin is pulling down to the screw when running.

In the last chapter of the book on the 850 Edelbrock, it says you may need to put smaller idle tubes for a more mild engine, this engine sounds like it has a cam, but I don't know what it is.

I was thinking of turning the idles crews in all the way to see what happens, they are about 2 1/2 turns out right now.

Also, when I bought the carb, the guy said it had been sitting in the box about 4 years, and had only been run on his car about a dozen times, it did look pretty new.

Oh yeah, the exhaust stinks, but then again I'm used to fuel injection with cats on my 99 Corvette, so that may just be the way a carbed, no cat engine smells?

[1965C-10]

This is when I bought it in 2009, I just put the truck back on the road May 2011 after doing a frontend rebuild, power disc brake swap, power steering swap.

So, it really sat for about 6 years since the previous owner ran it, until I started running it, I did not open it up or anything, just put a new base gasket, and turned the idle screws to 2 1/2 screws CC, and set the idle speed to my liking, and run 12 volts to the choke.

[1965C-10]

Also, I'm sure it still has the stock fuel filter in it, but I added and new inline fuel filter to it just to play it safe since I was concerned about the gas in my tank being nasty for sitting a long time, would the 2nd filter be bad for it?

[429bbf]

mike, nice carb id like to have it .id start with a by taking it apart and measuring every thing and buy a sr kit from cliff.if the engine is pretty stock id set it up with receipe 1.if cliff chimes in he can tell you just how to get it right the first time.i tuned on quads for 30 years and never got them right till i read cliffs book.now they run like swiss watches .dean

[Cliff Ruggles]

Those carburetors have a very generous idle calibration, and the large .149 inlet seat, and a crappy accl pump. 

I would rebuild it with one of our kits, and install smaller idle tubes at the same time, to provide more control of idle fuel for your application.  Unless you have a huge cam in the 396, it's not going to like the calibration of the 1910 unit......Cliff

[1965C-10]

 "Unless you have a huge cam in the 396, it's not going to like the calibration of the 1910 unit......Cliff"

Are you saying even with the smaller idle tubes and carb kit, the 1910 unit is too much for the mainly stock 396, or just the way it is right now?

Is there any other parts I should get while ordering the rebuild kit and idle tubes?

[Cliff Ruggles]

Smaller idle tubes will help with the stinky idle.  I'd put 71 or 72 jets in it as well, as those carbs have small MAB's and 73 main jets from the factory.  It will also help to open up the lower IAB just a tad while it's apart. 

I just set one up for a mild application, and doing these things really helped it out.  It's not too much carburetor for what you are doing, just too generous with fuel delivery at every level.....Cliff

[Cdennis]

I received a 1980 Camaro from my brother who passed a few years ago. Posting here because I recently found out that the car has a 8908  1910 2688  W Edelbrock carb. After doing a search for 1910 on this Forum I have been adjusting this carb. It seemed a little sluggish off idle sometimes so I recently purchased your book and a accel pump. The Camaro is being powered by a 1969 Pontaic 428. It has a performer RPM intake that is gasket matched to a set of mildly ported #12 heads. The camshaft is a XE 294 Comp cams a .519 x .524 lift 250@ .050 and 256@ .050 with a 110 center-line. The trans a turbo 400 2800 stall with a 3:31 12 bolt very spirted and fun to drive. It will idle in gear around 800 RPM in gear and 950 in park. The issue I have is a slight stinky rich smell but when I use 110 race fuel it smells great but a 8 bucks to costly. I have found a site wild bills corvette who sells Tetra-Ethel lead as a octane booster which for me has stopped my run on and slight detonation when mixed with 93 gives me about just over 100 octane. When I ran 93 octane only I still had similar odor. I have nto had carb apart since it runs really good but plan on a rebuild soon so I do not have any specs on the carb. Thanks for the read.

[Cliff Ruggles]

The stinky rich idle smell is the camshaft with 250 something duration @ .050" and 110LSA. 

It's a bit too much cam for what you are doing but manageable with correct tuning.  It's going to want timing and fuel so the 1910 shouldn't be too far off as they were made for big engines with "hefty" cams in them.

The 1910's have a few issues with the parts used in them so for sure order one of our kits for it. 

If you have control with the idle mixture screws no need to make any changes there.  Those carbs are also pretty generous for fuel delivery everyplace else.

Having to blend in higher octane fuel or octane boosters isn't a good scenario as it becomes difficult, if not near impossible to keep the blend the same tank to tank, plus expensive........Cliff

[Cdennis]

Thank you for the reply Cliff, I don't drive the car in temps under 50 so the choke is set lean. When i first fire engine during warm up idle smells good. It gets full warm then it starts to smell a little rich. Off idle part and full throttle work awesome, the car is a real beast out of the hole. The octane booster is easy 1 can to 16 gallons 103 from 93 is about 60 dollars fuel abs 25 bucks additive 5.31 a gallon beats 8 bucks a gallon. Stay out of the gas pedal it gets decent mileage. Forgot to mention full headers 3 inch to the axle thru x pipe 18 degrees initial 36 total hei with 6a

[Cdennis]

Used race fuel last weekend smelled awesome no rich odor.

[1965C-10]

Hi, I started this thread years ago, truck was parked and got it going this summer in June.

The truck was running much better than before I parked it, which I was glad and surprised.

One night I drove somewhere and was turning around in a parking lot very slow, just barely touching the accelerator pedal and it started surging like it was running out of gas and it died.

I tried holding pedal to floor and it started again, but since then anytime I'm just barely touching pedal, like driving down a residential street it surges and I once heard a hiss sound.

Today I tried playing with timing, no change, using my hand to barely open throttle it starts surging and I heard the hissing sound from what I think is the choke pull off thing, on front right (passenger side).

I tried opening throttle very slightly again a few times and it starts stumbling and then the hissing sound starts.

Maybe a bad rubber diaphragm inside that part?

[Cliff Ruggles]

Sounds like a vacuum leak someplace. 

I doubt if a vacuum leak a the choke pull-off would cause it to run that bad.  Check the gasket between the carb and intake, main castings and baseplate. 

Make sure the PCV hose doesn't have a rip in it as well......

[1965C-10]

Made a video but says too big to upload.

Replaced carb to base gasket, no improvement.

Passenger side of carb is damp with gas, so maybe the lower gasket inside carb.

Need to buy a rebuild kit.

[1965C-10]

I think I got it figured out!

Years ago I tried a upgrade I read about where you hook vacuum advance line to intake manifold, and not ported vacuum.

Took off vacuum line from HEI advance canister, plugged it with finger, slowly move throttle just a bit runs better, tried 3 times, put vacuum line back on vac advance, open throttle just slightly, it starts running crappy.

Also I added in a vac advance stop to limit vacuum advance.

Need to find or go buy vacuum line and hook back up to ported vac.

So vac advance too soon seems to make engine run like crap.

Still need to rebuild carb but maybe I can drive truck again.