Gone Johnson

Im pretty convinced that my recent hesitation / sputtering popping issue Im having when driving my Olds is a bad accelerator pump. Its intermittent, but getting worse. When I operate the throttle, nothing squirts out of the jets, and the area on top of the carb where the pump is, looks all oily and gunky.
When the carb isn't acting up, the engine runs totally smooth and awesome. Ive only checked the vacuum so far, which is at 18psi, and I have made sure there are no leaks, and that the hoses are all in place and routed correctly.
All that being said, does anyone think Im crazy? Am I on the right path?
And, can an accelerator pump simply be "replaced", without a carb rebuild?

TripDeuces

Easy to get:
https://www.summitracing.com/search/...ump-assemblies

But remember there is a gasket between the upper carb body and the main carb body. You don't want to rip it.

Gone Johnson

Ok, if all I got to do is be careful, remove the top of the carb, and swap out a pump, for 13 bucks, sounds like a simple quick solution. Assuming this is the correct diagnosis.
I remember when my Buddy installed my HEI dist, he messed around with the vacuum advance springs and weights for quite a while, and was never quite happt with the onstallation of them. This haa always been in the back of my head, as a possible cause of trouble. But, I dont know enough about vaccuum advance to know better.

oldcutlass

The vacuum advance is a canister, the springs and weights you speak of is the mechanical advance. If you have no fuel spraying when you operate the throttle it can only be 2 things, 1 is no fuel in the carb and 2 being a bad accelerator pump.

shiftbyear

Sometime videos help a lot. I typed in edelbrock 1904, also recurving distributors on youtube and several videos popped up. Good luck

Gone Johnson

Ok. That does it. It'll take me a few weeks, but I'm ordering and replacing that accelerated pump just because that's my gut, and also it seems nobody disagrees with my theory here. I will definitely post here what happens next because I know somebody else is going to need this info too. Thank you, and I will be here soon to tell you what happened!
still welcoming any other input, if anybody has any

Gone Johnson

...... also, I will wait to worry about that mechanical vacuum advance. It didn't look like the weights and springs were activating properly. So I'd like to start over again with those. Maybe a whole new distributor?

Gone Johnson

My Edelbrock 1904


Edelbrock 1904 Accelerator pump part #1982
(with cup that is resistant to modern fuel additives)


What I had to remove, to change pump

So, this is mostly reference. I know someone may come along some day with the same issue with this model carb.
If you ever need a part number on an Edelbrock 1904 (Q-jet style) carb, for the accelerator pump (which is part #1982) and you are like me, and want to see something actually say," yes, if you have THIS carb, then THIS IS the part# for you", you will never find it on the internet. I had to call Edelbrock, which is what I should have done from the get-go. Yes, there are many sites that may have had what I was looking for, but none specifically mentioned this carb. Just Q-Jet, and there are several different ones. And, to add to the confusion, there is a 1-barrel carb out there with the same model number.
The Airhorn gasket kit is Part #1987, in case anyone ever reads this.


So, did it work? Heck yeah it did! seems to run a lot better too. AND, when I operate the throttle, I get a couple of happy squirts again!
I'll take it on a long run soon, and then Ill be 100% positive - the symptoms I was experiencing were intermittent, so, Ill be more confident over time.


Thanks to each one of you guys who helped me with your invaluable input!

olds 307 and 403

I assumed it was an Edelbrock AFB clone POS carb. I have used that accelerator pump in Olds Qjet's, it worked fine. The short shaft spring in cup seal style with the red or blue seal is supposed to be the best.

Gone Johnson

Yeah... look at my pics above...I don't know why I did the things I did when I bought the aftermarket carb and manifold. I was real young. I musta thought the autoparts store guy was Dr. Olds. I was sold the wrong manifold (Edelbrock makes a non-EGR manifold, but I have this one), I could have had a Holly, or a different style Edelbrock, but I got this Q-jet, and had to cut off the bottom portion of the throttle so it wouldn't hit the EGR boss (They should have sold me a carb spacer)...... seems like Im always stuck with the unpopular sh*t.
Notice the throttle cable bracket I made... how about that trans cooler line?
Smog heads?? I didn't even do drugs....

oldcutlass

Glad its up and going again.

olds 307 and 403

The 2711 non EGR manifold has only been out a few years. Of course the RPM intake is very street able. That Qjet is a good choice, to bad Edelbrock only did the side inlet.

Gone Johnson

Eh.
Problem is back. Probably only put 100 miles on it since the big "I fixed it" celebration. I get sprays down the venturi still when I throttle it... inline clear fuel filter looks a little dry when running. For some reason I expect it to be full of gas when running.
Im having horrible luck with this.
A neighbor gave me a brand new Edelbrock Performer carb to throw on, and I cant even use it with this existing Edelbrock Performer manifold, because of the EGR boss getting in the way of the linkage. Id have to throw on a 2 inch spacer to make it work....
Then, he gave me an old Holly dbl pumper 600cfm, said it worked great when he removed it. so I threw that on, and the engine ran so bad, I couldn't turn screws fast enough before I realized gas was just pouring down the manifold. Garbage.
I don't feel I want to attempt a full rebuild. I guess a new carb? Could I have a weak fuel pump? What do you think?

coppercutlass

I ran a 1405 600 cfm edelbrock no issues at all in my 72 been in use for almost 10 years a few in my car then that whole engine went into my dad's pontiac. use a half inch spacer and bend the bracket to clear the egr boss.

shiftbyear

It's hard to tell, but it seems like the hose from the vapor canister is on the wrong carb fitting in the front baseplate (circled). Try capping the carb fitting and see what happens. If it runs better, connect the vapor line to the large uncapped fitting above the front inlet. Good luck

olds 307 and 403

It may just need a rebuild. I would get a good rebuild kit and a better accelerator pump.

Gone Johnson

The one you have circled (closest) is the dist vacuum advance, the one under (behind) is the evap. My understanding is the big fat one above is a bowl vent (does not "suck")
You still think I ought to switch/cap?

Gone Johnson

I know this thread is getting long, but I wanted to mention from back in the beginning, the engine runs perfectly smooth and awesome, until suddenly, and randomly, the popping hesitating choking - filling the interior with unbreathable raw gas/exhaust..... then, it goes away at some point, and is great again

scottv442

since this seems to be a reoccurring problem, that did go away for awhile, after you opened up the carb., my guess would be dirt in the fuel line or a collapsing fuel sock in the gas tank. this would cause all your symptoms to appear as they do.

disconnect the fuel line before the fuel pump and blow air back into the fuel line. you will hear bubbling from you gas tank without too much pressure. If this fixes the problem temporarily, then you have found the source of it.

shiftbyear

Yes, cap the evap at the carb and run. Also cap the large vent on the front, not needed and is allowing unfiltered air into the fuel bowl. Good luck