85 Chevy 305 hard to start

[esohn1]

Hello, this will be my first post to the forum, so let me say thank you for all the help. I have a 1985 Chevy c10 with a 305 and a 4bbl Rochester Quadrajet. When I first bought it (in February), it would idle very rough and was slightly hard to start when cold. But, it would turn over on the first crank once it had warmed up. Now, the problem has progressed to being extremely hard to start after the truck sits for 6 hours or more. But, it will still turn over on the first crank once it has warmed up. And, by hard starting, I mean it takes anywhere from 20 to 40 seconds worth of cranking and between 10 and 25 pumps in between the cranks (the pumps and cranks are broken up, not continuous). Sometimes, the engine will start to catch but wont have enough to sustain idle. I wouldn't personally say that it is related to cold starting, because I live in Las Vegas. And, even if I try to start it for the first time of the day at 3pm when it has been cooking in the sun for hours and it has been 110 degrees all day, it starts just as hard as if I start it at night. Once it is running, it run slightly rich. Also, when idling, there is occasionally a smell of gas. It is also runs much rougher when the a/c is on (not an uncommon problem). The spark plugs are brand new, and the carburetor has had a light cleaning. No change whatsoever. Upon observation of the carburetor, the fuel does not come out as a liquid stream when activated, instead, it appears to mist out, and the only positive indication of fuel actually entering the carb is burn off that comes back up and a sound of squirting. But, let me reiterate, I cannot see a liquid stream of fuel coming out. Which contradicts the rich running. The starting problem is getting progressively worse, as well. Any suggestions as to how to fix this problem are much appreciated. Also, let me say that any theory I have in here could very well be wrong as I am not a mechanic, just a life long gear head. Any help will be much appreciated. I will offer any additional details that are needed. Thank you.

[jaredts]

What is your normal process for starting it when cold?  Do you pump the gas pedal once and then turn the key or something else?  Have you looked at the choke's operation at all?  When you say it is hard to start you do mean that it cranks as fast as it should but won't start, correct?

[bd]

esohn1, if I interpreted your story correctly...

The carb may have leaking fuel well plugs (which require carb removal and disassembly for repair), and a float that possibly has just begun to absorb fuel.

Leaking well plugs allow the carburetor fuel bowl to slowly drain overnight into the intake manifold where the fuel puddles and gradually evaporates.  Hence, the carburetor is virtually dry when you try to start the engine in the morning.  The engine has to be cranked until the fuel pump can refill the carburetor.

A slightly heavy float will effectively raise the fuel level in the carburetor causing the engine to run rich, most noticeably when warm.

Raw fuel smell can result from overfilling (topping off) the fuel tanks and/or having a vapor canister that has saturated.  It can also result from running rich.

Have you replaced the fuel filter, spark plug wires, or the distributor cap and rotor?  They maybe overdue.  Is there a bulbous blue electrical connector on the top of the carb?

[esohn1]

Jaredts, When I say it is hard to start, I mean that when I first try to start it, I usually pump the gas pedal twice before turning the ignition. Then, I turn the truck over for about 5-6 seconds. Then I pump the gas pedal 4 or 5 times. Then, I turn the ignition for a few seconds, then pump the gas a few times until it will start. The truck will start to catch but it won't have enough to actually sustain idle. When it finally does catch, it roars to life. And, yes the starter works just as it should, the engine cranks as fast as you would expect it to. Also, I have looked at the choke and the pull off, but I have not taken them off. They seem fine to me. But, if there is something specific I should be looking at...

Bd, I have heard of the Quadrajet having well plug problems. The way you describe the problem makes a lot of sense to me. I have not replaced the fuel filter, spark plug wires, or the distributor cap and rotor. I have not even taken a look at them. I guess I just automatically figured a fuel problem based on the symptoms. I will take a look at all of them. And, yes the carb does have an electrical connector, that at one point I suspect was blue, but has been since dirtied. What is the purpose of this electrical connector? And, why do you ask about it? Correct me if I'm wrong. But, if you are right (and I suspect you are) the carb would need a rebuild, or a new carb. Correct?

[esohn1]

**UPDATE** The truck has also started to loose combustion while at high rpms. While cruising on the high way, it will jerk back and forth as the engine will generate power and start to die. The individual jerks won't last for more that a second, but they will come and go for minutes at a time. To me, that screams fuel delivery problem. Any thoughts on how the problems could be related?

[thefarmboy21]

Timing chain could very well be WORN OUT!!! Especially if it's stock.

[bd]

Inspect the tune-up components as mentioned: cap, rotor, plug wires, and replace the fuel filter.  To check the spark plug wires, unplug both ends of the wires one-at-a-time and look up inside the boots for black soot or greenish discoloration.  If you see soot or greenish stain, replace the wires as a set.  Measure each plug wire using an ohmmeter - factory style plug wire resistance typically measures ~3,500 ohms per foot.  For example, if a three-foot long wire measures more than 11,000 ohms, you should replace the set.

Beyond the tune up I think you have more than one issue causing problems.  Perform some basic diagnostic checks to help narrow it down:  fuel pressure and delivery, exhaust backpressure, ignition components, timing chain.  Each link explains the respective process.

[esohn1]

Thanks for the help. I will try all these things this weekend. Hopefully something promising will show up.

[87ChevyR10]

No codes thrown?