Got a 74 Cutlass Supreme..put some seaform in it about a week ago.
notice every now and then as I accelerate I get like a puff or hesitation then it immediately picks back up..do you all think the additive is still trying to clean or flow through the system?

 

I think if the SeaFoam cured your problem it would fix it pretty quickly. You need to figure out if the hesitation is spark or fuel related. Is your Cutlass stock?

 

It is the original engine

 

Check for boogers in your fuel filter.

 

The other thing to check is your mechanical fuel pump. Clean the entire fuel pump real good - top, sides, bottom, etc. Clean the area where the pump & gasket mount to the engine. Take it for a ride and get on it. Sometimes the gasket goes bad &/or the internal diaphragm begins to age. I had a hesitation develop on my 1971 CS 350cid & I was monitoring the fuel pump over several months time while the hesitation began to develop. I noticed some seepage/leaking. I replaced the mechanical fuel pump w/ a Carter mechanical fuel pump and new gaskets. This resolved my issue - no more brief hesitation on acceleration.

 

Both good points. The OP can also have the HEI module in his distributor tested at the auto parts store for free. Know that imported, or store brand modules have been known to cut out or fail when hot.

 

Good place to start. SeaFoam by design is a strong solvent. My guess is it cleaned some crud out of the tank and it ended up in the fuel filter. Might have affected the accelerator pump too, and entirely possible the saran filter on the tank unit may catch some of the crud too.

Change the carb inlet fuel filter, then install an inline filter in the fuel pump rubber suction line. Get a few of them because if the SeaFoam did its job they're probably gonna plug up again. Easier to change the inline filter than the carb filter and the less you disturb that fuel inlet the less chance of creating a leak.

 

Here is what the filter look like

 

Might not hurt to check or replace the accelerator pump plunger rubber.

 

Did the filter come out of the carb crushed like that?😳

 

That fuel filter is malformed and not to standards - unless the image has distorted the fuel filter (which may be the case as the image is terribly out of focus) the fuel filter should be straight - not bent & not warped, or whatever it is. Does this filter have a check valve or no check valve in the end? Whoever did the install crunched that filter which should not be the case. There is plenty of room for that filter inside the housing. The fact the filter is malformed/distorted may or may not effect fuel flow, but it is not straight which it should be.

 

EDIT: Thought (could be dangerous). Evaluate the fuel filter housing. It's possible a numbskull PO may have loaded up a buttload of plastic washers or what not inside that filter housing which crushed the filter.

 

In case you're unfamiliar. The fuel filter either does or does not contain a black check valve in one end.

https://quadrajetparts.com/quadrajet...-c-128_54.html

 

It looks like the wrong length fuel filter for your carb was used. It would most certainly mess with fuel flow.
https://www.google.com/search?client...t+fuel+filters

 

Pictures....make sure you have a spring in that housing correctly oriented.

 

Yes it did

 

Had a check valve

 

Sounds like you’re on the right path. If you have a fuel filter between the tank and the pump, change it out too. I think of them as cheap insurance. I usually opt for the steel ones, not the clear ones, just out of caution.

I completely agree with the others about the smashed inlet filter. I’ve never seen one like that. It doesn’t look right at all. Refer to the diagrams above for how the carb should go together.

If you have time & inclination, consider getting the tools & parts to learn how to bend up your own hard lines. The factory used metal lines between the pump and carb, but usually these get lost along the way and get replaced with rubber. Once you do a fuel line, vacuum lines are in bounds tool and you can make your engine compartment look really nice and just ever so slightly custom…

When you fire it up for the first time after any fiddling/replacement of fuel lines, keep a fire extinguisher handy and consider having a friend close by to watch for fuel leaks. You want the underside of the fuel inlet to be _absolutely_bone_dry. As in, it doesn’t make a paper towel even damp. And no gas smell at all. You want no leaks or you’re risking an engine fire.

Ask me how I know…

Chris

 

I will put my 2 cents in here, I agree with this post, BUT lets go one step further, Take off the air cleaner, grab a flashlight & look down the front section of the air horn, now open the throttle slowly and you should see a steady flow of fuel entering the throat of carburetor, if nothing is there the first pull of the throttle the accelerator pump is bad. fairly common. Do not open the throttle fast,,, [just slow & steady.] A fuel filter problem would cause high speed fuel starvation. engine falling on its face on the high way etc.. This is not a fuel filter problem.. If this were the case the engine would have long crank times to start up for lack of fuel in the carburetor float bowl.

 

I agree that fuel lines are preferable to fuel hose. What does vacuum hose have to do with it? You mean the OP should replace the vacuum hoses as well?

 

if the accelerator plunger cup is worn or damaged from ethanol it will cause issues, get an ethanol resistant one
good luck

 

Accelerator pump.
Also, a simple rebuild on that carb would be a very good idea.
Is that a 2 bbl?