52' roadmaster carter carb issues

**rapidride2** · 02-13-2011, 02:04 PM

I recently got my "farmers field find" 52' roadmaster up and running after many, many years of not running. It has a fresh tuneup. Miraculously the car idles fine and quickly starts right up after all it's years of sitting. The vacuum advance is also working properly. The car has the original carter 4 barrel carb.

Even after the engine is warm the engine has a massive hesitation/bog off idle. Only if i accelerate EXTREMELY SLOW will the enging keep up and increase r.p.m.'s smoothly. I realize it's a straight 8 but any type of normal throttle increase the engine and it falls on it's face.

I have a deluxe kit for the carb. I realize these questions are somewhat vague but is there anything else i can check? I was thinking bad accelerator pump,,, Is there anyhting i should look for before i rebuild the carb. Also, i have a new restored fuel tank, fuel pump and fuel line with a filter.

Thanks for reading.

**39CENT** · 02-13-2011, 03:45 PM

well a carter carb is usually a good one. seems to be tuning problems, and should be straight forward carb, ignition, etc. but sometimes just having 'old car', maladies there can be other problems. leaking manifolds, valves, so forth. Keep checking the Buick engine is a lively one, mostly a torq engine.

**BluesBrothersBuicks** · 02-13-2011, 07:50 PM

Howdy,

A bog off idle usually means the accelerator pump is shot. A quick way to check it is to look down the throat of the carb (down the front primaries if it's a four barrel - down both if it's a two barrel) while actuating the throttle linkage. While working the linkage you should see a good steady stream of gas squirt into the venturi. The venturi is the throat(s) of the carb where the air passes through on it's way to the intake manifold and head. It needs to be a steady stream of fuel and not full of bubbles or be intermittent. If you have a BAD bog - my guess is you won't see ANY fuel squirt out. This accelerator "pump shot" is compensating for the sudden rush of air going into the engine when you hit the throttle. This is the way - more or less - a consistent air/fuel ratio is maintained. The accelerator pump is actually a shaft with a leather or rubber or plastic seal on the end of it. When the throttle is pushed down - thru mechanical linkage - this shaft is pushed down into a "well" where there is fuel. Because of the seal - the fuel is pushed thru passage ways and into the venturi. Bottom line is - if you have no "pump shot" or just a dribble of one - you have to take at least the top of the carb off and replace the accelerator pump because you have to get into the inside of the carb. And, if you are going to do that - then I suggest you have it rebuilt by someone who knows what they are doing. Holley provides a service to rebuild ANY carb. I am sure it will be expensive but, I expect it would be a top notch rebuild. I have never used this service so you might want to check around and get opinions from others. Hope this helps out. Any other questions? Just holler!! Thanks, BluesBrothersBuicks

**rapidride2** · 02-14-2011, 09:43 AM

Originally Posted by BluesBrothersBuicks

Howdy,

A bog off idle usually means the accelerator pump is shot. A quick way to check it is to look down the throat of the carb (down the front primaries if it's a four barrel - down both if it's a two barrel) while actuating the throttle linkage. While working the linkage you should see a good steady stream of gas squirt into the venturi. The venturi is the throat(s) of the carb where the air passes through on it's way to the intake manifold and head. It needs to be a steady stream of fuel and not full of bubbles or be intermittent. If you have a BAD bog - my guess is you won't see ANY fuel squirt out. This accelerator "pump shot" is compensating for the sudden rush of air going into the engine when you hit the throttle. This is the way - more or less - a consistent air/fuel ratio is maintained. The accelerator pump is actually a shaft with a leather or rubber or plastic seal on the end of it. When the throttle is pushed down - thru mechanical linkage - this shaft is pushed down into a "well" where there is fuel. Because of the seal - the fuel is pushed thru passage ways and into the venturi. Bottom line is - if you have no "pump shot" or just a dribble of one - you have to take at least the top of the carb off and replace the accelerator pump because you have to get into the inside of the carb. And, if you are going to do that - then I suggest you have it rebuilt by someone who knows what they are doing. Holley provides a service to rebuild ANY carb. I am sure it will be expensive but, I expect it would be a top notch rebuild. I have never used this service so you might want to check around and get opinions from others. Hope this helps out. Any other questions? Just holler!! Thanks, BluesBrothersBuicks

I was thinking possibly thinking the accelerator pump as well. i will check for fuel squirt in the primaries upon acceleration when i get a chance. Thanks for the input....

**histbuff1190** · 02-15-2011, 12:10 PM

Never seen one of these with a factory 4bbl carb--to the best of my knowledge it was either a 2bbl carter WCD single or twin 2bbl carbs for the straight 8's. Was it running right before? Or is this a development from it sitting for years? Might be too big a carb or a timing issue (maybe stuck advance weights keeping the timing retarded until the vacuum kicks in). One more thought is that the gas went stale. What carb is it exactly? How long has it been sitting?

**Straight Eight** · 02-15-2011, 02:08 PM

Originally Posted by histbuff1190

Never seen one of these with a factory 4bbl carb--to the best of my knowledge it was either a 2bbl carter WCD single or twin 2bbl carbs for the straight 8's. Was it running right before? Or is this a development from it sitting for years? Might be too big a carb or a timing issue (maybe stuck advance weights keeping the timing retarded until the vacuum kicks in). One more thought is that the gas went stale. What carb is it exactly? How long has it been sitting?

Very rare, but actually used on 52 Roadmasters only. This is why they are not seen very often.

**telriv** · 02-15-2011, 02:27 PM

Actually the '52 RoadMaster 320 straight eight was the 1st. big 3 production using a 4bbl. I remember them being Rochester's, but also could have been a WCFB or a Stromberg.

**rapidride2** · 02-15-2011, 02:41 PM

It's the carter wcfb on this 320. It is definitely the accelerator pump. It's squirting nothing at all.

Next question,,,,, how comprehensive is the carter wcfb manual that is sold for around 10 bucks??? I have a nice kit with alot of hard parts included. I would like to find something a tad better than the shop manual..... Anyone rebuilt one of these wcfb's???

**Jim Carmichael** · 02-15-2011, 09:12 PM

These are easy to rebuild and just remember you are not trying to see how many small parts you can reduce the carb to. Just take it apart far enough to clean it up good and if you shoot the holes with cleaner make sure you protect your eyes!

I have used the service that Holley provides and it was great. I had them restore the tri-power set up on my 63 Galaxie and they looked brand new. Well worth the money for a show car but not needed for a driver.

**rapidride2** · 02-16-2011, 09:48 AM

Has anyone ever used the carter service manual that is out for these carbs on cd rom for around 10 bucks?

My kit is good but NO INSTRUCTIONS! I bought it from the carburetor shop in Eldon , Missouri. I have a buick service manual but i was looking for a little more detail along with an exploded view.