I got a new and maybe a simpel problem. again.

i fitted the intake manifold 390327 on my 350 olds engine.
than i bolted the 4bll carb 704225 on it.

But mt problem is its running on to much feul and it's backfirering.
Did i bolt on a Q jet carb that is to big? a bigblock carb?

than a other problem the carb has a lean and rich round thing on it like my 2bll. But the intake has not the conectionpart on it (vacium metal pipe thet runs trough the outletpart in the middle.
The intake has a other type of thing a bemetal bolt on part that not conects the round lean/rich part of the carb.

Can it be build otherwise? that should be great.

I want the engine to run first before i go on with the sanding and respraying my olds 88 conf of 69' .

And have anyone the propper schedule of the vacium hoses of a Qjet? has it a outlet to a vacium advanced hei?

Kind regards,

D Appeldorn

 

There were two kinds of choke mechanisms used. The earlier one was called divorced choke because the bi-metal spring was actually mounted in a well in the manifold and operated the actuator to the carb. The later one had the bi-metal spring mounted on the carb itself in a round pod operating a shorter actuator to the choke plates. Don't know what it was called. Can't mix the two. You need to get the divorced choke actuator and remove the choke pod that is on the carb (I don't think you have to replace the carb). Or, you could get a different manifold that isn't set up for divorced choke, it has a heat tube the exits out of a plate and transfers the hot air (sourced from a vacuum port on the carb, sort of a closed loop) to the bi-metal spring mounted in the pod. You should be able to see the port for that, I think is faces the firewall. As is recommended so many times, get yourself a service manual, it will be worth the investment.

Edit: Sorry I forgot you are in the Netherlands, hard to get parts. Maybe someone here on the site can help you out. You still have the problem of mis-matched carb and manifold though....

 

there should be one more digit at the end of the 704225.
the olds 704 series carb. has the integral type choke. as another alternative to replacing the manifold or the carb; you could put an electric choke on the carb. or, you could even go with a manual choke, but personally, that wouldn't be an option, for me.

the rich/lean adjustment only affects choke operation-not the rest of the metering system on the quadrajet. you could try a little experiment to see if it's the rest of the carb. that is having problems:
after the engine is warmed up, loosen or remove the three screws that hold the choke cap on. using a small flat blade screwdriver, pry lightly between the black choke cap and the choke housing to loosen/remove the choke cap. trying to turn the choke cap using the screw head looking part of the cap won't work-you'll break the cap-guaranteed. after you remove the choke cap, the choke valve should move to wide open. take the car out for a ride and see if it's still "acting up". if it is-you have other problems. if not-the choke is the source of your problem.

let us know what happens.


bill

 

That black circular cover labeled Lean >>>Rich is made from what I always referred to as Bakelite material, it is very brittle and will break easily, so I second Bill's caution.

 

Than i can remove the choke part of the carb.
I disabled the vacium hose of it for a try by puting a screw in a hose on it.

the choke valve? are they the 2 smaller airinlet on the carb? they are wide open.
But the 2 bigger valve's don't get open.
I tried to open those and the engine is running better.

My question was if the carb fits a 350 engine becouse it's running on 2 much feul.
I think in the futere to change the carb and maybe the intake.
But i need a good runneble car before i can sand and respraying it.

And i don't need the choke becouse i only use the car for fun driving in the summer.
Tho if i can remove it i can replace it later with a electric one or buy a new carb with intake.
That only if the engine works, if it's not i gona replace it.
It stood 10 years in a barn and don't know if its good, but it runs

The last number of the carb i don't know, its stamped with a up side down T

If anyone can help me with a service manual it would be a great help.

I go to try those options tanks by the way, and let you know if it's better.

kind regards,

D Appeldorn

 

Check out this book. It will help you out a lot in understanding everything.
http://www.amazon.com/Rochester-Carb...3217628&sr=8-3

 

On a Rochester 4 barrel carburetor, the two front openings have some metal "doors" on the top, these are the choke plates and should be the ones that are actuated by the choke mechanism. When it is cold enough, if you depress the accelerator pedal fully and slowly one time, the choke should actuate those plates and they should close almost completely. This closes off much of the air entering the carburetor and makes the air to fuel ratio richer (more fuel than air). When you have that round choke mechanism loose and turn it toward "rich" WHILE THE ACCELERATOR IS DEPRESSED or the cable is manually pulled, you should be able to cause the choke plates to close. Doing this to a pre-determined gap between the choke plates and the openings is how the choke is adjusted. Different engines require a different measurement, but to estimate in general about 2 centimeters is good.

edit; you have to do this adjustment when the bi-metal strip is cold. I have done this during warm weather by placing that assembly in the refrigerator or freezer to simulate cold weather.

 

I refitted the vacium hoses and turn the choke plates to wide open (lean)
He runs much better now, but it's stil slow on the trottel.
If i press the gaspadel to fast its stalls. i have to rev up the engine by push the padel slowly or in stages to rev up.

if i push the gaspadel to fast it still occasionly backfire's

But it runs better than befor and i just started sanding, might i need a engine or carb adjusment? fine tune?
Those bigger valves on the carb don't open.
And can i conect the vaciuum advanced hei on one of the smaller conections on the carb? they ar on the top of the carb as a vaciuum below the valves.


D Appeldorn

 

the choke valve should be FULLY CLOSED before starting a cold engine.
the pull-off opens the choke valve a preset amount after the engine starts. there is a specification for setting this(choke pull off adjustment). this specification is carb. number specific.


bill

 

sounds like your accelerator pump is not working.

the rear air doors won't open until there is enough throttle opening and air flow. this is how the quadrajet is properly sized to it's application-automatically.

you can connect the distributor vacuum advance to manifold vacuum. plug any un-used vacuum ports on the engine/carb.

you may be looking at a carb. rebuild here, btw.


bill

 

I mounted the aircleaner, and it's much better now.
But i go to try those answers out maybe it helps to finetune the carb.

I don't attend to sell or throw it away, the carb i mean.
But why a rebould? are the Q jets of rochester better than a 700 edelbrock carb?

And if it's runs well, it's stay's on the car.

D Appeldorn

 

as far as a possible rebuild goes-i'm just going from what symptoms you've posted. i sort-of "do" quadrajets for a living.

a quadrajet, properly set up, will run better than an edelbrock. an "out of the box" edelbrock isn't set up exactly to your engine like your quadrajet may be. you'll probably have to set up the edelbrock yourself, to get it to where it needs to be. this may mean changing internal parts until it runs perfectly.

yes, i wouldn't throw-out a qj either. they're not making them anymore and they're getting harder to come by.


bill