Carb problems

[Ben Bruce aka First Born]

Having carb/fuel problems on my 1950 Mod 52. Starts and idles like new. I have removed and cleaned the glass bowl and ceramic filter. Checked the screen in the carb inlet. BUT when I attempt to accelerate, she wants to bog down. If I close the choke slightly, it will pick up and go. The float bowl level is right where it belongs. Checked flow of gas at inlet to filter, and is good. Did not check pressure. But glass bowl stays full.

Carb is a Carter WCD 725s.

Hoping Jon will come on and suggest what to check next.

Thanks

Ben

[carbking]

Ben - LOTS of possibilities. My suggestions, in order:

1. If you have a Pertronixs conversion, put back in the points and condenser.

2. Test the distributor advance mechanism

3. Test the carburetor accelerator pump

4. Check the idle mixture screw setting, average setting 1 turn, MAXIMUM setting 1 3/8 turns

5. What octane fuel (you should probably be using 87), and is it fresh?

If none of the above fix the problem, call me.

Jon.

[NTX5467]

Sounds like a lean condition. Once you get it moving at about 30mph, how does it act when you throttle into it? Less bog? The same? The choke, slightly closed, still helps? With the choke "applied", how does it act at cruise? As in "slightly rich"?

Carbking, is the Pertronix not suitable for that application? Just curious.

Thanks,

NTX5467

[carbking]

NTX - we have had lots of first-time customers call with idle and low speed issues and Pertronix. Replacing the Pertronix with points and condensers has solved many of these. One customer, who also happened to be an electrical engineer told me all electronics like stable voltage. Vehicles with generators do not have a really stable voltage at idle and low RPM, as do vehicles with alternators.

Not saying the Pertronixs IS the problem, but based on experience, it would be the first thing I would check.

Jon.

[Ben Bruce aka First Born]

Jon, thanks for your input. Still have points. They actually only have a few hours on them. Checked them and ok. The problem seenes to me to be a lean condition, as NTX said.

I have removed the ceramic filter "cartridge" from the glass filter. Bowl is full. Tried checking the distributor vacuum advance, but my vacuum pump took a dump. This engine is original, but was running good. Will work on checking fuel pressure at carb inlet as well as vacuum at various locations. May be first of next week.

Thanks

Ben

[Guest brh]

Its been quite sometime but I had a problem of bogging on my 65. I went to check my vacuum advance by pushing on it from the inside with my fingers. Gas shot out. Needless to say there was a crack in the carb. My point is you might be able to check it by pushing on it and putting your finger over the opening (after ya pull the hose off). If it holds, at least ya know there is not any leaks in it. Hope this helps.

[Rosiesdad]

Check the two long brass tubes inside the carb attached to the top. Make sure they are clear of deposits.

[60FlatTop]

Was the car alright before you put the new points in? If they are not old stock Delco they might not be any good. And if you put a new condenser in you could really be in trouble. The Bosch boxed condenser I put on my '60 Electra had the condenser end wire just drop off while driving. Junk that took a long boat ride.

I am stocking up on all the original Delco parts I can find, including generator and alternator parts. Mexico, India, Korea, just can't duplicate our old USA stuff.

Bernie

[Mark Shaw]

I had the same problem with my 38 Special.

It has two fuel filters, so I didn't think anything could get through.

But when I finally checked, I found crap partially blocking the main jets.

[NTX5467]

Check the two long brass tubes inside the carb attached to the top. Make sure they are clear of deposits.

From my experiences, those brass tubes might look good, even flow Berrymans B-12 spray carb cleaner through them, but if there are drilled orifices near the end that's in the float bowl, there can STILL be deposits in there. It might not cause a bog, but more like a "not want to idle" situation, from the solid tubes (which are idle fuel feed circuits), with the larger tubes with the holes in them for the main circuit.

Only sure way to determine if they're as open as they need to be is to probe them with "something". In my case, it was a bent-wire spark plug gap gauge. I started with the smallest one and progressed to larger sizes, with the gauges openning the orifices up more each time, until it could not be put in them anymore. Then I got a twist drill assortment, including something close to the largest gauge I'd used, and then carefully drilled "until I struck brass", then stopped, blew through the tubes, then flushed them with carb cleaner, and then re-installed the venturi cluster. THAT problem was something that took a good deal to find out about and then fix!! Just because I could get carb cleaner to flow didn't mean there was ENOUGH flow, as I found out.

Just some thoughts,

NTX5467

[Rosiesdad]

Yes NTX, very true. My giant flat spot was caused by a brass tube that was ever so slightly restricted. I think it greatly affected the vacuum level.... thus the gas level in one side. I carefully cleaned them both till they matched and Bucky pulls like a locomotive now. Well he did until that inattentive Bxxxx hit us from the rear. Grrrrrr

[Ben Bruce aka First Born]

Well, after all the good ideas on here, I pulled the carb yesterday. pulled it downm to the point I could remove the metering rods. They did not look too bad, but cleaned them any way. Made sure the jets are open and clean and reassembled.

Now for a test! Started, after priming until carb refilled itself. Sounds good. revved the engine. So far, so good. Now for a drive. One block, two blocks and then the same old thing!! Any opening the throttle gets a "starving reaction. Close the throttle to idel position and all is well. After a few blocks, turned around and headed home. Discouraged is not even strong enough. About four blocks from home, accelerating from a stop she suddenly kicked in and ran like a TOP. Rest of the way, like a Buick should. ???? Will try driving again in a few days. Will keep you updated.

Thanks to all who offerer suggestions.

Ben

[JohnD1956]

... I swear, these freaking cars have a mind of their own...

[pirate]

When an engine bogs down upon aceleration it is almost always one of two things. Auxilary pump in the carb or spark advance in the distributor. Simple test for both. First with engine not running, air cleaner off look into carb venturi (you might need a flashlight) open throttle wide and observe two good shots of raw gas flowing into the venturi. It is the extra gas needed for the engine to excelerate. No shot of gas? Take carb apart clean pump passages and don't loose the checkball and replace the pump plunger. Todays gas is a killer on a lot of these old plungers. For the distributor spark advance you can use a timing light. disconnect the spark advance vacuum line and make sure the timing is in the mark. then rev the engine and observe when and where the centrifical advance moved the spark back. Then connect the vacuum line to the vacuum advance and you should see a noticable difference in the distance the spark advances. If no differnce in advance first make sure you got vacuum to the system and if so buy a replacement advance diaphram.

[carbking]

Generally speaking, carbs do not have a "personality". They either are consistantly bad, or consistantly good.

While theoretically, it is possible that the carb had a big hunk of crud that finally blew out; a much more likely culprit is something in the ignition.

Jon.

[Ben Bruce aka First Born]

Jon, thank you. I value your opinons. And you may be right. But as stated in first post, if I close the choke slightly, seems to pick up and go. This while standing beside the car and choking by manually closing the choke.

I think I will pull the top off carb again and make CERTAIN the metering rods are free. Will keep all informed.

Ben

[Ben Bruce aka First Born]

Well, I pulled the top off the carb and the metering rods are free. Push them down[closes] , release and they pop back up[open]. Reinstalled top on carb and started. SUCCESSE.

Took it for a drive. Performed flawlessly. I surmiss the rods or the piston that operates them was binding when this problem first reared its ugly head. When I cleaned them last week, there may have been a little dirt still in the system, although I did not see any. Maybe a passageway from the drfice to carb throat partially blocked. In any case, all is well now.

Next on this car is removal of the oil pan and bearing check. Will post this endevor on Me and My Buick under Bens 1950 Super Mod 52.

See ya there

Ben