1950 starts, idles, dies when I give it gas, but...

[Guest ClubHabel]

... So my Buick Special will start, idle fine, and if I give it a lot of gas the car dies. However, from an idle if I can slowly get the rpm's up, it'll run and as long as the rpm's are up, I can continue to give it gas, rev it, etc, with no problems.

Ive had the carburetor rebuilt, gas tank relined, blown air through the gas lines, and have no clue what the problem is. Any thoughts?

Could probably use new plugs and wires, but didnt think that would cause this problem.

[Guest Straight eight]

:)Sounds like the accelerator pump in the carb. Remove air cleaner from top of carb, without the engine running. While looking into the carb pull back on the rod connected to the gas pedal, there should be two strong jets of gas squirting like a squirt gun. If it is squirting, then the spot where the squirt is aimed may not hit the target, and the carb rebuilder should be contacted to aim the accelerator pump output if the ideas below do not help.

It sure sounds like fuel starvation. Clogged fuel filter, weak fuel pump, choke not operating on start up. You don't say whether the condition contiues after warm up.

Oh yes one more thing the gas cap. It should be vented. Try removing the cap or at least loosening it one click and see if that makes any difference. TIGHTEN THE CAP DOWN AFTER TESTING.

Has someone plugged the exhaust system? Maybe a mouse nest? Does the exhaust sound swishie or just the deep throated roar of Buick exhaust?

[Guest ClubHabel]

When I look in, I can see the 2 squirts of gas (2 barrel). Where should they be squirting onto?

[Guest Straight eight]

There is a measurement in the manual and probably in the instructions that came with the rebuild kit. Not all carbs are marked.

[Guest ClubHabel]

Sorry, I didnt see the rest of your comments initially. I'll check the rest. I too am suspect of a weak fuel pump.

[Guest Straight eight]

Try the site for Antique Parts Cellar (correct spelling) for a fuel pump. He can rebuild yours, or sometimes is able to make an entirely new pump with his parts stock.

You can email him at

oldpartstom@aol.com

[Pete Phillips]

If your fuel pump is an older rebuild, or just an NOS one from many years ago, it won't last one month with the lousy, newly formulated gasoline that we have today. I just got a 1958 Studebaker running, after 40 years of sitting idle. The fuel pump worked for about two weeks (total of 4 miles driven in that time--to the gas station for its first fill-up, and back home). The fuel pump then promptly failed, and I had to get it rebuilt last month. The lousy gas destroyed the old diaphragm in the original pump in no time at all.

Pete Phillips, BCA #7338

[Guest Straight eight]

The Antique Parts Cellar uses modern material impervious to the new fuel to rebuild and make new fuel pumps.

[Bhigdog]

It may not be the gas, Pete. I generally avoid anything NOS that's made of rubber or other organic materials. A lot of old parts like that fall apart just from old age while still in the box........Bob

[David Childs]

If the running problem turns out to be fuel pump--the best rebuilder of these is Terrill Machine in Texas. They advertise in HMNews. They have rebuild all my fuel pumps through the years with never-fail expertise.

[rocketraider]

I can second Pete's fuel pump comment. I put an NOS pump on one of my 64 Oldsmobiles, and less than 50 miles later it's junk.

I'm not so sure I believe all this hooey about gasoline being the finest it's ever been. Seeing too many fuel related issues on old and newer cars. Rather ridiculous having a specialized blend for every podunk town in the country too, though the EPA says we must.

[NTX5467]

"Gasoline being the finest" might depend upon whose talking and where they are placed in the fuel situation. "Finest" from quality of production and lower emissions is not generally "finest" when it comes to vintage vehicles. Fuel has been regionally blended since (at least as I remember) Texaco started advertising that theirs was blended for specific regions of the USA . . . way back in about 1965.

Oxygenated fuel was tried in the Denver area in the winter months to help with their air quality issues, something like 10 years ago? Now it's called "reformulated" gas and we've all got it in one form or another as oxygenates are now a normal part of most gasolines anyway. I suspect that the ozone non-attainment areas might get blends with more than the other areas, possibly.

I tend to concur with Bhigdog's comments about NOS rubber parts and age. Allegedly, all automotive rubber hoses and such made since about 1990 are tolerant of the flaky fuels we tend to have today.

As for the carb issue, it could well be that the fuel calibration "holes" inside the fuel feed tubes of the carb are plugged up with old fuel additive deposits. The air bleeds on the top of the venturi cluster might be open, but the fuel orifices inside the tubes which go into the float bowl area could be clogged and preventing a proper mixture getting into the motor at "moderate to higher" engine loads. From my experience with clogged or restricted-by-hard deposits orifices, they are really hard to trace down as to where they are, but when you find them and get them cleaned out, then things work well again.

You might be able to squirt some B-12 or carb cleaner through them and they all look fine, but they can still be clogged. Even a "professional soak and rebuild" will not remove them. They have to be found, then probed with increasing wire gauges (I used a bent-wire spark plug gap gauge) and then finally cleaned with appropriately-sized twist drills going just big enough to get some brass in the shavings. Then clean things out with some spary carb cleaner, reassemble, and things should be fine.

Also check the power/economizer valve for proper functioning. The accel pump's shot covered the initial flatspot when the throttle is openned, but it's the power valve that enriches the mixture for when the engine's under load. If the spring on the power valve is broken, it can keep it closed longer than it needs to be for best engine operation.

With the oxygenated fuels, sometimes it's necessary to richen up the main jetting a few notches to get things to work better. Getting things working with the existing production jetting, first, would be best, though.

Just some thoughts,

NTX5467