I have a '74 Century with the 350-2. I got it this weekend, and until today, it was running good getting up to highway speed. Under normal acceleration, it ran fine. But try to accelerate quickly, and it sputtered and chugged. So I figured, I'll spray down the carb, run some cleaner, see how it does. I'm very tame when I drive. But today, it gave Krystal (my fiancee) problems driving. It ran fine in the morning, fine in the afternoon, but then it started having problems. At idle, it'll rev up just fine. But put it in gear, and the idle lowers, and giving it much more than minimal gas causes sputtering. And that is all it does is sputter, doesn't speed up even. Give it more, and it wants to stall, and backfires. Once was enough to say "It's off the road till that's fixed." EDIT: The following was in the original message, but was inaccurate. [Above 40, it runs fine. She said also that it runs good when it's going around a corner. All this together tells me it is probably carburetor related, although whether it is fuel or air I don't know yet.] I'm not sure how much of that is relavent, but any help is appreciated. I'm still learning carburetors, not that I ever learned much about injection systems. I have got to find a decent manual soon. I'm not sure if someone got my vacuum hoses mixed around, or what it is. The plug wires are ZIP TIED together. I'll be stealing wire holders from my other car to straighten that out. I was running 87 octane, I put in 15 gallons of 93 to top it off though tonight.
Someone suggested the fuel filter. But my concern is that it revs up fine in neutral/park, but when it's put in gear, it seems to only want to idle. I'll be looking for the transmission fluid dipstick tonight I guess. With it running ok above 40, I have to wonder if it's stuck in 3rd if that's possible.
At first I was thinking fuel filter too.....then you mentioned it running fine above 40mph. A plugged filter pretty much acts like an rpm limiter. I would still change the filter anyways - cheap insurance. Personally, I prefer a good sized, quality inline filter - and take out that little filter at the end of the fuel line (in the carb). I would agree with the above suggestions.....sounds like time for a carb rebuild. Make sure you take a strand of wire or use compressed air to blow out all the tiny passageways. The 2 barrel carbs are quite easy to go thru....very few parts, compared to a Q-jet. Might be a good time to check some of the obvious things......vacuum line condition, spark plugs & wires, cap/rotor, etc. You might also want to have the condition of the distributor checked. Make sure the vacuum advance is working, parts aren't worn/broken, etc.
I cut off the twist ties holding the wires, put in some wire holders, and then, lost the keys into the defrost vent. After retrieving them today, I drove the car, and in fact, above 40mph it is doing the same thing. Won't take more gas, just cuts out and stumbles. I guess before I thought it did ok, because it accelerated quicker, so I didn't notice.
Well I did the wires, plugs, cap, rotor, and the fuel filter. It was running great, drove it to the store for a vacuum line. Got on the main road, and it drove good. There was a slight stumble, but after that, it accelerated good! Then sitting at a light, I felt it shake a little, and the idle didn't sound right. Took off from the light, and it was like before- bogging with anything more than minimal gas pressure, felt like it was going to stall. Traffic started going around me, not being able to get over 20mph without bogging. It seems to me like it's flooding? Like sitting at that light let the fuel accumulate too much, then when it's time to go, it lets too much gas in, making it bog? Does that sound reasonable? I still have the carb spray and Sea Foam to go yet. I'm guessing a float is sticking or something. Maybe the float level, but I've read elsewhere not to mess with float levels except as a last resort. Being that I don't know where to begin to look for a float, I think I'm safe there.
From your description now after the work you have done, sounds like your float is sinking causing gas to overflow the float bowl and seep into the carb.
Ok, so the float is sinking. What could cause that? Basically if it comes down to a rebuild, I'll have to take it to someone. If it's something I can do with it on the car, then I might make the attempt.
Doug, I think you are running lean. I don't believe you are flooding out. It is one of two things. Either the float is sticking, and not allowing enough fuel into the carb, or your fuel pump is going away. Next time the motor starts acting up, take the air cleaner off, and look down the throat of the carb. If it is flooding you will see raw gas pouring into the throat. This usually stalls the motor(that's why I think you have the opposite problem). Next take a wrench, and tap the fuel bowl. This sometimes temporarily frees up a stuck float/needle-seat. A fuel pump that is going bad will also give the same symptoms. Fuel pumps are cheap and easy to put in. If the pump is old, replace it, it's good preventative maintenance. Good luck.
Right now the only time it's acting up is in gear. It idles and revs in neutral or park just fine. And currently, it only does it after sitting in gear without moving for a good length of time, like a stoplight, or waiting to turn for a long time. If it starts choking I have been able to back off on the gas, accelerate slowly, and eventually it isn't noticable, I can accelerate again. I know lean is bad, so maybe I'll try tapping the bowl before driving, and see if it does it still. The bowl is the plastic part, under where the fuel filter is?
Frequently, a motor will rev in neutral and park just fine, and stumble under load, when the fuel level is low.
Fuel pump is only $20-30, guess I'll take a stab at changing it out. The pump is in the engine bay, just follow the fuel line down to it, correct?
Yes, Drivers side front of engine. 2 mounting bolts, and fuel line connection. When bolting it back up, you may need to rotate the engine if the new pump doesn't fit flush.
Ok, think I found the pump. Also noticed an open hose- coming off of the charcoal canister (?) the big black cylinder at the front driver's side. It has 2 hoses coming out of it, one labeled "Tank" the other labeled "Carb". The one labeled "Carb" was hanging down in the engine bay. Where's that hose connect on the carb?
It probably goes in the end of the air cleaner snorkel. Take a look at the snorkel. Is there a hole at the bottom , on the very end?? Wish your problem was that simple.
Yes there is, and it just reaches that spot too. I wasn't sure, but thought it might go there. But it said Carb on it, so I figured maybe it goes to a connection on the carburetor. I'll hook it up there, makes sense. (vapor from the gas tank goes to the can, and recycles into the intake) That's just extra, I'm sure that's not THE problem. I hooked the other connection under the air cleaner to the vacuum source at hte front of the manifold. There were several things connected there, and one of the connections had a cap on it (cracked too) so I connected it where that cap was. I did get the fuel pump changed today. To give you an idea of my ability, it took me from about noon till 3, then from 6 till 8, to get the old one out and the new one in. 5 hours to do a fuel pump. I'd bet a shop would have had it done in 30 minutes. But it only cost $20, and I got the experience of doing it myself. There's some satisfaction in that. It's doing the same thing as before though. Push the gas slowly, and it goes ok. But there's a spot soon after where it cuts the engine out, it basically stalls, till you let up on the gas. Push it a little more past that spot, and it sputters. I'm thinking now maybe since most everything else that's been mentioned has been replaced, maybe the timing is off. I don't have a light, so maybe for what it's worth, I might be better off checking if the local shop will set the timing for a fair price. When the engine is cold, I didn't notice the choke plate being down, to block air flow. It doesn't move that I can tell. One last thing I can think of that isn't connected, I think it's the heat riser. What connects under the air snorkel, down to the connection on the block. As I understand it pulls warm air in to speed up warming up the engine.
I took it to the shop around the corner from my house. They drove it, adjusted the timing, points, and dwell, and it now runs much better. Only a slight hesitation where before there was a good 4-5 second pause. They said the next step is a new carburetor. Mine has the choke tied off (figured it wasn't right) and I'm guessing could use a rebuild or replacement. But for the time being, it should be plenty good enough. All for less than $30. Better than me buying a timing light, trying to figure it out, and then there's the whole points/dwell thing, which I know nothing about at this time. I dropped it off yesterday around 4pm, it was out waiting to be picked up when I stopped in at 9am. I told him I was stopping in just to make sure they knew it wasn't a Chevy 350, because I'd heard of a lot of shops not making the connection. But he was aware of the difference.
I was pleased that they were realistic in not expecting me to want to rebuild/replace the carburetor, suggesting I drive it first. I think they knew if I drove it, I'd be out the door for only $30.
