It ran ran Fine Yesterday, well kind of, and now it doesn't start

Before I get into the diagnosis path, an waste time in the hot day, as we're having a heatwave here in New England. Does anyone have an Idea of how this might have happened?

Saturday Morning (about 65°F)
1. Truck sat all week I push the pedal to the floor 2 times.
2. Turn the key, engine made about <1 revolution and started right up.
3. I drove the truck a few times (5), one trip I had gone about 50 Miles of driving.

Sunday  (about 85°F)
1. I push the pedal to the floor 1 time.
2. Turn the key, engine made about <1 revolution and started right up.
3. Drove the truck 3+ times during the day. short trips around town (<15 miles round trip)
4. On Sunday evening I drove the truck to the store,
5. Came back out side after about 10 Minutes, tapped(<1/8th) the gas with my foot (I don't know why)
6. Turned the Key, and it did not start at all
7. Pressed the pedal to the floor and cranked, still nothing
8. Took the air cleaner off Pinned the Choke and the throttle plates open, and went back into the store for about 10 Min.
9. I was hoping to find some starting fluid in the store but there wasn't any.
10. Kept the Choke plate open aby released the Throttle
11. Cranked the engine, nothing
12. Waited about 10 Minutes with the Choke and the throttle plates pinned open
13. Pumped the Throttle a few time while cranking, and it seemed to turn over slightly faster.
14. Walked to a gas station and bought the starting fluid (took about 5-10 Min)
15. Un-pinned the choke and throttle Plates sprayed a shot in the the carb (<1/2 second spray)
16. Cranked engine, it did not fire.
17. Gave it a full 1-second spray.
18. Cranked the engine fired right up drove it home. - drove an operated fine.

Yesterday evening (about 90°F)
1. Truck sat all week I push the pedal to the floor 2 times.
2. Turned the key, it did not fire up.

I've read a little about Vapor-lock and it sounds similar however I would have though it should fire right up like normal yesterday.

I think all the specs of the truck are in my signature but it's a 351W, with the 2bbl.

Anyone here have a similar issue? Could it be due to the heat, and exaggerating another issue I may be unaware of? i.e. timing or mixture?

You didn't say how far it is to the store, but if it isn't far and the engine was still needing choke then everything you did up to the shot of ether may have been in the wrong direction.  But the long shot of ether was enough to get it going.

So here's my guess: Your carb is giving the engine a slightly lean air/fuel mix at idle, which means the engine would like a bit of choke to get started.  But if the choke was set slightly lean then the fairly high ambient air temp may have it already coming off just enough to prevent the engine from starting.

I think I'd pull the air cleaner on a hot day but when the engine hasn't been started, crack the throttle slightly to let the choke set, and see where it goes.  If I'm right it won't close very much, in which case I'd dial in one more notch on the choke and see what happens.

Crud in the carb maybe? How old is your tank? Do you have a clear filter before the carb and if so, what does it look like?

I am thinking that junk from the tank may be making its way into the carb and blocking certain smaller passages, maybe in the idle circuit, which is where it would be drawing fuel when you are trying to start it and your foot is not on the gas. Those circuits are pretty small and most susceptible to being blocked by junk.

Then when you gave it a good shot of the starting fluid, it fueled the engine enough to get fired, and that turbulence dislodged the sludge?

It's a theory, anyways...

Temps here have soared from the 70s to the 100s. I have had some hot start issues the first time I fire up the F350. Sounds just like your problem.

I attribute it to the choke setting as when I started it when it was cool early yesterday there was no problem. Chokes do need seasonal adjustment if you have wide temperature swings.

Gary, Pete, and Gsm, Thank you guys for weighing-in on what I felt was a stupid issue.

Pete, I feel you man, I went through 3 Carb-cleaning episodes until I replaced the tank with a plastic one. I haven't checked the in-line frame I added between the pump and the Carb, but I figure it's not too bad. If it had been 2 years ago before I replaced the tank I'd dig into that. Thanks. I went with a plastic one from this place:
https://www.justgastanks.com/1980-1984-ford-pickup-2/

Gary and Gsm, The choke may be the culprit, although it seemed fine on all of the other days. Gary to answer you question the store is about 5 or so miles away, I figure the choke would be open by then. Just to clarify, are you guys telling me that by pinning the plates open, I was giving to too much air? and pumping on the gas would not have made it rich enough to fire?

... and in from from the peanut gallery at work: Possibly Vacuum Leak? But again, I haven't seen a significant change in low rpm performance...

Even if I include the Peanut Gallery's comments, I only have 3 things to check, this seams better already

1. Fuel filter
2. Choke Adjustment
3. Vacuum Leak

Do I hear any takers on Ignition timing?

Thanks again,

Yes, with the choke pinned open you may not have had enough gas to start a "cold" engine.  And especially if your idle air/fuel mix is lean, which can happen if you don't have it adjusted correctly or have a new vacuum leak.

Said another way, I don't think it is a timing issue, although that can cause problems.  I think it is an air/fuel ratio issue.  And I think when it isn't starting that you have too much air and not enough fuel.  That may well be due to the choke not coming on far enough, or a vacuum leak, or both.

How does it run when it is fully warmed up?  Is the idle steady and at the same RPM it has always been at?

Alex,

I am guessing this is your first going with a motor that has a carb?
Every motor with a carb will have its own process for starting for when it is cold or hot outside and the same for the motor if cold or up to temp.
The trick is how long will it take for you to find it LOL

The other thing that dose not help is today's fuel.
It is not made for motors that use a carb and the reason why we have issues like this and mostly hot restarts.

Dave ----

Dave,

Not my first engine with a Carb, but the first time I'm doing things right with a Carb'd Truck.

******************8Gary and Gsm ! You guys were right! TOO LEAN***************

1 Turn of choke plate adjustment screw (5?)and it fired right up. I tried it just before and  I started and nothing, it didn't matter when I even pumped the pedal. I stopped, I went and turned the screw, voilia! Started it right up.



I knew I asked the right crew, so happy I didn't go diggin' into anything too deep,

Thanks again

Congrat's!!!!  Glad you got it going.  

That’s great!

Fantastic!

Bulletproof250 wrote

Dave,

Not my first engine with a Carb, but the first time I'm doing things right with a Carb'd Truck.

******************8Gary and Gsm ! You guys were right! TOO LEAN***************

1 Turn of choke plate adjustment screw (5?)and it fired right up. I tried it just before and  I started and nothing, it didn't matter when I even pumped the pedal. I stopped, I went and turned the screw, voilia! Started it right up.



I knew I asked the right crew, so happy I didn't go diggin' into anything too deep,

Thanks again

It was not meant to put you down but we have a lot of new owners that have never owned a carbed motor and whatneeds to be done, move throttle to set choke, before starting.

Good to hear just a little adjustment and it is better.
Dave ----

No offense taken here Dave, we're cool.

I can 100% understand the situation, I've always been pretty good with Carb tuning on my smaller engines, but this is the first time I've really explored it with something that I drive regularly.

Thanks again,

Wait! It happened again,

I suspect that I'm just a bit close to the edge of properly adjusted. Is there any check I can do or procedure I can perform to ensure the choke is adjusted correctly?

Could you describe "it" a bit more?  

In other words, tell us what it did and didn't do when you did this and that.  I suspect you have just a bit too much or too little choke, but we need to see some detail to guess which way.

Hey there Gary, and Bullnose crew,

... yeah that a Good Plan, here's a bit more detail,

Hopped in the truck yesterday mid day (it had sat all night) it was already about 85-90°F

Pushed the Pedal as usual

Turned the key it fired, Idled rough, then died.

I returned to cranking over the motor with no response,

Took off the air cleaner, and gave it at shot of staring fluid (since that saved me last time)

returned to cranking, still nothing.

Tried some more starting fluid, cranked it over, same outcome, nothing. (repeated 2 more times)

I returned the Air cleaner, and tried it one last time, She fired up, a bit rough but then got to idling as normal.

I assume that this is "too lean" condition but I figured I should bounce that idea off some experts first. I had rebuilt the carb last year and had made some Choke adjustments which until now have not failed me.

I assume I need to adjust something but figured I ask be fore I started turning screws ;-)

I think it is a bit too rich.  The fact that it started, idled rough, and then died and wouldn't easily start with ether says rich to me.

Most chokes have the ability to floor the throttle and open the choke up to get past a too-rich situation.  You might pull the air cleaner and open the throttle fully (with the engine off but coldish) and see if it opens the choke.  If so, then that's a way past that problem.

But the correct way is to loosen the three screws and back the choke off maybe 1 notch.

Yeah I have to agree with Gary, your description of this latest episode sounds like it is rich, to the point of flooding. If it happens again where you can't start it, press the gas pedal all the way to the floor and hold it there (no pumping, just mat the gas pedal). Then crank without letting off the gas. If it then starts, that's flooding for sure. The reason holding the gas pedal to the floor works in that situation is, you have way too much fuel in there so the mixture is very rich. Opening the throttle all the way lets lots of air in there too, thereby leaning out the mixture.

Thanks Gary and Pete for your diag'

I wish it wasn't raining today, or I'd be trying it right away once I got home. Better luck tomorrow. I'll post and update this week, after I dig into it.

Update:

Today started (figuratively only)just like the other "didn't start" but really, not a puff, nothing. Cranked it, w choke on, with foot to the floor, with starting fluid... nothing. So i checked for some spark, the old fashioned way screwdriver in the plug boot held near some metal crank it look for something, and I saw nothing. I grabbed the timing light, clamped it around no1 Cyl. figured I'd see a flash, still nothing. Absolutely not lying when I tell you that, I just ordered an ignition module for the truck today, because the wiring is pretty worked over and I wanted to freshen it up a bit. So now, to ensure I'm doing the right checks, I haven't looked at the "Documents" yet but once I post this that's where I'll be.

I'm open to any checks I should do before I start changing things around, So that I don't end with the same problem, because it's actually rooted somewhere else in the engine.

I'm all ears,