Carburetors For 1950 Oldsmobile 88

[BillV]

1949/50 Oldsmobile V8s came with Rochester or Carter carburetors. Are there any modern day two barrel carbs that will bolt on the stock manifold and will operate with stock throttle linkage?

Over..

Bill V. [color:"blue"]

[carbking]

What would you consider modern?

The O.E. Carter was/is as good (opinion) as any other 2 barrel produced, AND it is calibrated for the engine (anything else would require recalibration). I am not a big fan of the AA series Rochester.

Jon.

[BillV]

Jon,

I was hoping there was an inexpensive off the shelf Holley or other brand name 2 barrel that would work.

I have the AA series Rochester that works fine at low speeds but chokes/starves out at higher RPMs. Rebuild kit didn't fix the problem. I also have a remanufactured AA series Rochester coming.

Bill V.

[Guest keeffer]

are you sure its the carb and not your fuel pump

[carbking]

Bill - as keefer mentioned, this symptom could be a result of a defective fuel pump. It could also be a partially clogged fuel filter; or a plugged gasoline tank vent.

If the carburetor is the cause, something to look at would be correct parts and operation of the economiser (power) circuit. The economiser actuater valve is very expensive, and if not working will cause the economiser valve to always be open. This would cause a very rich condition much of the time. As some rebuilders do not wish to invest in the actuater valve, often the economiser valve IS REMOVED, and the passage plugged, in the hope that the unit will be placed on a "show car" and thus the power circuit never used. This will allow the carburetor to function on the idle and main metering circuits, but will run extremely lean under WOT conditions. Others not recognizing a defective economiser circuit and very rich low speed running, will alleviate the symptoms by compensating for the economiser with smaller main metering jets. Again, this will allow for decent operation on the idle and main metering systems, but very lean under WOT.

The original Carter uses the same proved design of the other Carters of the day. The Carter uses the metering rod principle, thus the corresponding part to the Rochester economiser actuater valve would be the vacuum piston spring which comes in the better repair kits. The only disadvantage to the Carter (opinion) is locating the O.E. air cleaner for the Carter (or the adapter that allows use of the Rochester air cleaner).

Check the fuel pump, fuel filter, and gas tank vent first.

Jon.

[BillV]

Thanks much for the advice. I have a new fuel pump that I can install.

Where is economiser actuater valve? Is that the Actuating Assembly - Power Valve?

Fuel tank was flushed and coated. Problem existed before the tank was flushed, but vent might be an issue. I've also installed new fuel line all the way back to the tank. Line was flushed. New in line (see through) filter installed.

Installed new plugs, distributor cap, and rotor with no change in symptoms.

The Olds has aftermarket modern spark plug wires. A friend tells me these 6 volt vehicles run better with old style wire plug and coil wires. What do you guys think?

Bill V.

1950 Olds 88

[carbking]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">

Where is economiser actuater valve? Is that the Actuating Assembly - Power Valve?

Bill V.

1950 Olds 88 </div></div>

Yes.

Jon.

[BillV]

Jon,

Thanks.

That fine fellow in Missouri that sold me the CS-846 kit in December included one in the kit. It appears to be functioning.

Regards,

Bill V.

wwvjr@cox.net

[carbking]

If the power (economiser) system is functioning, then I would look elsewhere than the carb. Even though everything is new, it might be interesting to do a fuel pump volume test (this should be described in your factory shop manual). Possible, although unlikely, that the new fuel line may have had some shavings. You can test for a clogged tank vent by drilling a hole in the center of an old fuel cap and using that. As a general rule, the AA would work well under WOT conditions (assuming the power system functional); its problems were in part throttle operation.

As to the spark plug wires, modern wiring is probably much superior to the original IF the proper wires are used. If radio suppresent resistive wires were used, this could be an issue. Modern high performance copper wire should function well. Same thing would be true for modern resistor-type plugs.

Jon.

[BillV]

The Olds is running fine! Installed new AC Delco R45S plugs, new spark plug wires, new fuel filter, and while I had installed new fuel line from tank to fuel pump, I had not replaced the fuel line from the fuel pump to the carburetor. Took fuel pump off to make sure all screws were tight and tightened several screws. Upon close inspection, I found the fuel line was badly kinked where it exited the fuel pump. Fuel was flowing through it, but it was very restricted. Also, installed new fuel line from fuel pump to carburetor.

Thanks to all for the help, etc.

Bill V.

1950 Olds 88