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350cfm Holley 2bbl probs. Alright this is the 1.8L Chevy luv of my buddys, problem is when you lightly touch the gas it will hesitate and buck and if you mash the gas and hold it it will do the same thing. I thought it was feeding too much fuel, so jetted it down 45 40, also checked accel. pump and timing. Im stumpped on this one, think it could be vaccumm related? I would get out my vaccumm gauge but he seemed to have blocked off all the intake ports, the only place I could do it off of is the carb, would that get a good reading? Also theres about 1.5 inches of spacers between the carb and intake. Any ideas on what the problem could be?


Eric

It could be a number of things. How old are the cap, rotor, plugs, points, and wires? Is the ignition timing correct? Maybe there's an air leak somewhere. Do the valves need adjusting? Is the motor stock? Is the exhaust system stock? If everything is basicly stock, you might be trying to run with a carb thats a little to big. Open up the exhaust. its pretty restrictive to start with.

_________________
Previous setup: 4.1 Buick V-6/TH 350
Current setup: 400 Small Block Chevy V-8/TH 350
9" ford rear end/short bed/blue
What do Water, Electricity and Humans have in common... They all travel the path of least resistance.

Motor is all stock. Rotor cap and wires are all fine, points Im kinda worried about, they are firing on half the side, exhaust has a header and 40 series flow right after the header, And I wasn't aware the valves on this motor are adjustable, are they? Thanks, so far.


Eric

You didn't mention what year truck you have. I stand corrected! I just noticed that it's a 79 model. The early year Luv trucks had the dismal, dual timing chain motor that had adjustable valves. I dont think the later Luvs had adjustable valves. Are all of the emissions control stuff still on the motor or are they removed? If there still on, you could have air leaks in all of that jazz. A quick test to see if you have air leaks is to cover the throat of the carb with your fingers. Slowly try to close off the opening of the carb. If the RPMs increase, there's a leak. If the engine dies, no air leaks. You might want to experiment with the timing after you address the concerns with the points and verify no air leaks. I destroyed my stock motor 2 weeks after installing a new Weber 32/36 DGV(it had major air leaks at the intake gasket). Ignition timing and idle RPM is crucial for carb adjustments.

_________________
Previous setup: 4.1 Buick V-6/TH 350
Current setup: 400 Small Block Chevy V-8/TH 350
9" ford rear end/short bed/blue
What do Water, Electricity and Humans have in common... They all travel the path of least resistance.

Also, Is the distributor vacuum advance disconnected when you set the ignition timing and basic carb settings? And when you connect it back up, are you connecting it to the correct port on the carb? If the vac-adv isnt connected to the right port or not connected at all, it will stumble and even backfire thru the carb.

_________________
Previous setup: 4.1 Buick V-6/TH 350
Current setup: 400 Small Block Chevy V-8/TH 350
9" ford rear end/short bed/blue
What do Water, Electricity and Humans have in common... They all travel the path of least resistance.

Ahhh, thanks for the ideas, I will look at all of them tommarrow when I see my buddys truck, I was just thinking about the vaccum advance myself, I will check out all of this, and I will post back. Thanks a bunch!


Eric

Covered the carb, no change in idle, maybe a little down but not much, I checked the vaccum advance at the diaphraghm and it was pulling vaccum at an idle, so I switched it to a ported vaccum source, didn't change anything.... I also hooked up my vaccum gauge, the valves are out of adjustment, but I dont think it would make that much of a difference..I will adjust them friday anyway.....Im thinking this is just to big a carb. Thanks for the help.


Eric

Try going at it from scratch. Set the ignition timing and idle RPM with the vacuum advance disconnected but capped to the carb. Adjust the mixture screws and reset the idle speed as needed. Reconnect the vac advance and make sure the idle doesn't rise when you connect the vac line. If it does, that means your connected to a manifold source. If it holds a smooth idle, most likely the valves do not need adjusting. Is the new carb brand new or used? maybe the accelerator pump is acting up? Did you test the vacuum diaphram? If its malfunctioning, it wont advance the ignition and it may be an air leak. Try spraying the carb body, base gaskets, intake manifold with carb cleaner or WD-40. Carb cleaner will make the engine stumble if there's a leak and WD-40 will make the engine idle up.

_________________
Previous setup: 4.1 Buick V-6/TH 350
Current setup: 400 Small Block Chevy V-8/TH 350
9" ford rear end/short bed/blue
What do Water, Electricity and Humans have in common... They all travel the path of least resistance.

Fixed it, I decided my drop in jets was way to big, I went back up to a 64 and a 50 then severly bent the acc pump linkage, problem solved!



Eric