Still having issues with my carb on my 55 Oldsmobile super 88. I’ve rebuilt it, correctly, and some times it still misses like if press fast on the gas it’s like it isn’t getting the fuel right away. It’s gotten a bit better with some adjustments to timing and air mixer screws. The only thing I have not replaced is the isolator plate, the one I have on could be the original from 55 I’m not sure. It seems to be made of a rubber material with thin metal layers. Could this be causing a vacuum leak that’s leading to this issue?

 

Read through this thread and post #17
New findings on the 4CG accelerator pump problem - ClassicOldsmobile.com

 

I’m thinking this a carb issue, but is there a reason why my 55 olds would flood so easily. I’ve noticed if I go to cold start it and pump the gas a few times it doesn’t want to start but if I don’t pump it will start slow but easier. I’ve also noticed a change in starting since I adjusted the timing.

 

Be certain your A/F mixture is correctly established AFTER you ensure you have set dwell & set timing. Dwell "MUST" be set before setting the timing. The following sequence must be done in order. Dwell effects timing, timing does not effect dwell - make sure you perform this in the correct order. Finally, set your A/F mixture ratio.

(1) You must set dwell to CSM specifications;
(2) You must set timing to CSM specifications; and,
(3) You must set A/F mixture screws to highest achievable vacuum.

Ensure your air/fuel (A/F) mixture screws are correctly adjusted. First, ensure all vacuum hoses are connected, secure & not leaking (no cracks). Using a vacuum gauge, adjust each A/F mixture screw to the highest achievable vacuum.

 

Ive set the AF before but maybe it’s changed since I gapped my spark plugs I’ll try those things in order tho cuz something’s not right.

 

A/F mixture screw settings are not going to mysteriously change after you set the gap on your spark plugs.

 

I agree which is why something else is wrong. It used to fire up after a few pumps of gas then I could shut it off for a few min and it would fire right back up now if I do that it acts like it’s flooded.

 

You used to pump it a few times before you rebuilt the carb because the carb wasn't running good. Now when you pump it a few times you are flooding it. If all the adjustments were done properly when you do a cold start one pump to the floor sets the choke and it should fire right up. If it's been sitting for a few days to a week it might need to turn over a little bit to fill the carb back up, but don't keep pumping it.

 

your exactly right and everything thing is working good now minus the accelerator pump still has a little hesitation but I figured out why it wasn’t starting and sounded like crap, some how the point got moved and weren’t closing! And I put my plugs back to .30 gap and bam fires right up. Still gotta set the timing tho.

 

It's unusual for the points to move more open, usually they closeup.

 

Read Post #4 - AGAIN.
Dwell>Timing>A/F Mixture
EVER TIME
Take-nothing for granted.

 

well my distributor is the original so I can see it happening maybe the base plate is loose, I’ve never taken one apart. Do they come apart, for cleaning purposes?

 

I remember and that’s what I’m gonna do today

 

If it ain't broke, don't start breaking it,try working on one problem at a time till solved. Then move on to what is the most important issue at that time. When you get more than a couple problems going at the same time, many times the fixes work ageist each other, confusing the problems and the diagnosis. Go slow and learn each part of what you are working on, it will save you time in the long run...Tedd

 

I agree, I was just curious. I’m not taking that distributor out ever again until I know it’s junk. Last time I pulled it up just a little to put the rotor on #1 and it took me about 20 min to get it seated all the way down I about had a heart attack I thought the gear on it fell off down into the engine but I didn’t know because it was still hooked up so I couldn’t take it out all the way.

 

question for you. I set my timing to 14 degrees because out here the elevation, so does the dwell change to? Meaning different from the manual dwell.

 

No. Dwell (point gap) remains same.