Technical Priming

Hey everyone! Posted over the last few days about my Chevy that died in the parking lot. The fuel gauge is one of the things that doesn't work on the truck, so I've been trying to estimate fuel on trips. I believe there is a chance I may have completely let her run out of fuel.

After fixing all the grounds, and battery connections, she is turning over like a beast! Really wonderful. The only issue is now I believe the lines are dry. My fuel filter looks somewhat okay, fuel level is pretty low, but I'm not getting any fuel shot into my carburetor now. Even when I disconnect that fuel line, it's bone dry. So my question is, is there a way to Prime the fuel lines on a 1954 truck? Anything I can do at the mechanical fuel pump? Thanks a million! I feel like I'm almost there.

 

Fuel pump should pick up the gas. Maybe the carb is not yet filled with gas, which is why you are not seeing a fuel shot yet. Just pour a little in the carb and crank it. Should get enough gas in the carb. It's possible you have a crack in a rubber line on the suction side of the pump. But I doubt it.

 

When you say pour a little gas in the carb .. right there in the neck? Flip the choke valve down and squirt inside? Or am I actually wanting to open the carb and fill the float chamber? Thanks!

 

Charles, just squirt/pour a bit [ tablespoon amount } right into the top of the carburetor. Should not even have to open the choke . We old timers even have been known to choke one by holding a hand on top of the carb.
And I would go at least 5 gal in the tank.

Ben

 

Thanks so much! I'll give her more of a dollop and see what happens this evening. I will mention I had a spray bottle and spray some into the carb, but now I'm thinking it both may not have been enough and also probably evaporated in the time it took me to crawl back into the cab haha

 

Watch out for a backfire from the carb if you do pour some gas down it. Sometimes they will do that if they are dry and raw gas gets into the manifold. I always put the breather back on after I pour gas down the carb, and nut it down. I have had the pop and blow the breather off if it wasn’t fastened, and have had them throw burning gas all over the under hood, not fun!

 

So I've poured gas in her carb... Have at leave 7 gallons in the tank.... No dice. Great strong, fast cranking... Nothing.

 

Could have put too much gas down the carb and flooded it. Have you checked a plug to make sure you have spark?

 

Yes we have spark, checked that yesterday. I'm totally perplexed. It just doesn't make sense that I'd been driving fine for 4 days and then nothing. And even better cranking than ever before.

 

I've had a couple of those inline 6 motors. Most definitely had to make sure they were on flat ground and then prime the carb with a splash of gas when I ran it dry. (No gas guage)Perhaps you flooded yours on your attempt. Try again and use a spray of starting fluid, see if it works tht way.

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You have gas, and spark. Do you have compression?


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If the tank ran dry has it sucked some shit up from the bottom of the tank that is now blocking the outlet?

 

Have gas, but can't get it to where it needs to go just yet.

 

I'm definitely going to go throw the system from tank to carb this week. Fine tooth comb time!

 

Old Chevy 6?
You said you have spark.
And you put fuel down the carb.
Should fire.
But as David asked...do you have compression?
The fuel pump and the distributor are driven by the camshaft. If your cam gear broke, (and the non-metal ones do) she won't fire even with gas and spark.
Remove the distributor cap. Does the rotor turn as you crank the engine? Or pull the valve cover. Are the rockers moving as you crank the engine? Or remove a spark-plug and put your thumb over the hole. Is there compression as you crank the engine?

 

Thanks so much! I'll go through each of these things, but almost positive i've got compression. Still this is all things to add to my list to go through it piece for piece.

It's the most bizarre situation. Drove for 5 days, and too my knowledge we MAY have run her out of fuel... That's all I know. Since then the only thing I've changed has only made her turnover better!

 

If you pour a tablespoon of gas down the carb throat, or use a shot of ether (“starting fluid”), you have enough gas for it to fire off, at least a couple of bangs ought to happen.

I’m thinking you have no compression. Timing chain, camshaft, gears, something around that area. I had a lawnmower do that to me last year. Ran great, until it didn’t. Had gas, spark, but no camshaft, so no valves, and no compression. It died with the exhaust valve open, so yanking the rope with a hand in front of the exhaust seemed like it was moving air, but it wasn’t. First symptom was that it wouldn’t start after seeming to run out of gas.



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If it cranks "better" and by that if you mean it cranks "faster" then you might have less or even no compression because the cam gear or chain has broken and the starter has much less load to turn.
Pull the dist. cap and check for rotation. Ralphie

 

But shouldn’t the pistons be hitting any open valves if the crank is turning but the cam is not? You would think at least a couple of valves would be open enough to be hit by the rising piston.....

 

BamaMav, I suppose you could be right, I'm just trying to help.

 

Not always, depends on it being an interference engine or non interference engine

I would doubt it would hit but not positive.


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It might have a fiber timing gear. They can basically just disentegrate. As was said, see if the rotor is spinning, or remove the valve cover and see if the valvetrain is operating. If the gear I'd toast, neither will work. I don't think the valves and pistons on those old hot water sixes collide when the gear craps out. My dad said there was just a no tic left loss of power and the windshield wipers would go crazy.

 

So does this sound right for checks? Will get on it this weekend.

Pull fuel line from carb and turn key... I should see fuel squirting ( from pump )
Remove dist cap and should see rotation on ignition.
Remove valve cover and see if all is okay.
Check the entire fuel line system ensuring vacuum and completeness.
Check fuel tank for possible blockage.

 

Depends on the engine. Maybe. Maybe not.



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Nice old 3W, Charles.
You've got the right idea.
I'd pull the distributor cap first to check for rotation. If it's not turning, you have some fairly involved repairs to make. (but not daunting) Your timing gear could be broken, or you could even have a cam that's broken in two. More likely, a bad gear. But if the rotor is turning, then the cam gear is good, the cam is turning, the fuel pump is being driven, the distributor is turning, and you can move on to other possible causes...
...a lack of spark or fuel.
If you disconnect the fuel line and put it in a container and crank the engine to check for flow, be careful not to splash or spill gasoline. And keep any trouble lights using a regular light bulb AWAY from the fuel. A single drop of gas will pop the light bulb, ignite fumes and you've got a fire.
One more thing for now...
You said you have spark. Where did you check? You need to check where the the spark plug wire clips onto the spark plug. If you have a good, snappy, blue STRONG spark, you're good. If it's orange and weak, you probably have a bad condenser. No spark at all, there's a problem with the distributor, coil, wiring, etc.
If you have spark, then the cam is turning...and I think you just have fuel blockage somewhere.
Good luck. Let us know how it goes.

 

Rather than pouring gas into the carburetor, FILL the carburetor bowl by using a squeeze bottle through the bowl vent.

Now you can test the accelerator pump.

And you give the carburetor a chance to put the proper amount of gas in the engine.

Plus, the chance of a backfire taking out your eyebrows is minimized.

If you ignore the above, and pour gas into the throat of the carburetor; first open the choke butterfly, pour in how much gas you want to use, AND CLOSE THE CHOKE VALVE!

Filling the carburetor is safer.

Jon.

 

If he has spark, doesn't that mean the distributor is turning? How would he have spark otherwise?
That doesn't mean the cam timing gears haven't slipped out of position. Gene

 

Of course you're right, Gene. And I don't really think that's the problem. I think it's fuel-flow. But I don't think that Charles has a ton of experience with this stuff. So though he said he "has spark", I don't know how he determined that.
Charles?...

 

My little brother took each plug out and I turned the ignition. He said we had spark.

I'm beginning to think it might be fuel flow as well. It really is the last piece of the puzzle. And it would make sense if I did indeed run the car dry and now she won't start.

As for the fast cranking. She used to have that really sluggish 6 volt sound when I would start the engine. Usually took 2-3 tries to be honest. But the second we put new grounds on and big 1 gauge terminal post cabkes, she is turning over with fury haha... The cab really rocks haha. That faster turn over... That wouldn't cause an issue with anything else would it. Like I don't have to adjust anything else now correct?

My hope is that I'll discover something in the fuel system and then she'll run better than she ever has before. To be honest I'm shocked that it's happened in the first place. Had a week of solid driving, and her previous owner drove her from the city to the farm on many an occasion.

 

FYI... it was mentioned earlier about whether the pistons would hit valves if timing gear was broken, what happens is with a 235 that the connecting rods hit the cam if that cam is not turning in sync with the crank and it won't turn over so if ever the distributor doesn't turn but you can crank it over that would most likely be the roll pin sheared or dist gear broke. Just info for future use. You should get a full 12 volts to the + side of the coil when cranking it over for starting.