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this might be lengthy but im aggravated and want to explain. I have a 1947 chevy truck with a 454 in it. ive had it for about two ywears and it was completed by someone else, it sat for about 10 years . I bought it. and ran great ! no issues. it was like a daily driver , I drove it all the time. the car ran very rich , to the point the back of the truck was covered in oil/gas . you could write your name in the greasy residue that was left after driving on the freeway. I then adjusted the carb. I'm running a summit street/strip 750 carb. the bowls are half way up the front window and the bottom of the back window ( was told that is the level to be at). took the car out, ran great no issues. then.... im driving the car ,went to hit passing gear and the carb stuttered and stalled. started right back up , drove fine at low speeds but if you wanted 60 your going to have issues. I love driving the car, I continued to drive around my area at low speeds . that worked for about a week. then at low speeds the car would hic up and stall , but start right back up. it sounded like it was running out of fuel. I thought the fuel pump was going bad. I replaced the fuel pump and went to a electronic fuel pump instead and added a fuel regulator. just took the car out for a drive and same issues at low speeds again. im lost ! im thinking accelerator pump in the carb? or just adjust the fuel back so it runs very rich again? any ideas? please help
 

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Moving to Basics forum. Introduction forum is not for tech questions. Thanks
 

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Not enough accelerator pump shot will cause a stumble when you step on the gas, but it won't prevent you from going over 50-60 mph....so it isn't the problem.
You mixture adjustment to a leaner setting isn't the problem either, not if it ran fine after adjustment.

How good was your fuel filter?? These carburetor designs have the main jets and the powervalve channels in the bottom of the bowls facing up, any dirt/rust/deteriorating hose/debris that gets in the float bowls easily clogs these up.
Very sensitive to not having a good fuel filter.

You adjust it, take it out and run it hard, it runs just fine for a bit, then you jump on it and all of the sudden have issue...sound familiar?? All the dirt gets stirred up and sucked into everything.

Now that we have ethanol alcohol in gasoline in higher percentages, 10%, it eats old hoses from the inside and loosens old varnish in fuel tanks.

The strainer "sock" in the end of the fuel line in the tank can get plugged too.

I'd start with a internal cleaning of the carb, and a flow check of the fuel pump/line...see how fast the line to the carb will fill a 1 gallon can.

That is a great carb design...but it has to be kept clean with a good fuel filter.
 

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My knee jerk is the timing set jumped time. Maybe not, but I've seen this before where an on the edge of worn out mixed with getting on the throttle as a somewhat unusual event suddenly results in lost top end, but the engine starts easily runs decent till you get on it.

Not that that is the only cause of such behavior but I'd take a peak at the timing, if you need to advance it that might be an indicator of deeper problems. I'd also have a look at the plugs and their gaps, get them down around .030 and see if there is an improvement.

Pumping unburnt fuel and oil out the exhaust is not good sign for engine health.

Bogie
 

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thank you

thanks for your replies to my tuning issues. the biggest question I have now is its at all speeds , literally cant do 25 mph now. the more fuel , more stutter then stall. I will check the timing on it tomorrow and clean the heck out of it. its progressing getting worse. started on freeway but now just normal driving . it could be timing but it sounds like it wants more fuel. ill check in again tomorrow and see if I found anything . thanks again for all the replies , I do appreciate it.
 

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when I put in the electric fuel pump I added a new fuel filter between the tank and the fuel pump . I also have a filter before the carb, both are new. I also replaced all the lines just because of the new fuel pump, all are also new.
 

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the car ran very rich , to the point the back of the truck was covered in oil/gas . you could write your name in the greasy residue that was left after driving on the freeway. I then adjusted the carb.
JMHO, I'm thinking you're motor is falling on its face because it is (and has been for a long time) jetted waaay too rich. With your plugs fouled making it even worse.
 
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