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Not a fuel issue?

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FrazerJames

Not a fuel issue?

Ok, I’ve run all new nylon fuel lines, replaced the tank and fuel sender. It’s getting uninterrupted fuel now.

Yet, I’m still stalling after about 10 seconds in idle. I suppose I need to dig into vacuum lines now?

1983 Bronco 4.9 300 I6
Current Name: Whitney

Gary Lewis

Re: Not a fuel issue?

Administrator

As you've started a new thread, which is fine, I don't have the history to easily review. So, can you remind us if this is 10 seconds from initial start of the day, or any start?

And, haven't the symptoms gotten worse? Didn't the truck run for several minutes initially? Help us understand how things have gone from that to now.

Now to the question at hand, perhaps you have too much choke. If the choke is set too rich the engine could easily start after setting a few minutes and then stall because it is too rich. Let it sit for several minutes and it would do it again.

So pull the air cleaner and start it. Does the choke stay closed or does it pull off a bit as the engine stalls?

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

FrazerJames

Re: Not a fuel issue?

I considered keeping the same thread, but was trying to be cognizant of proper subjecting. But you’re right, I should have at least brought over the history.

Yes, it was able to drive for a few minutes prior to replacing the tank and fuel line. The line was definitely gunky and had an air leak. I’m wondering at this point if the carb was adjusted with those issues present. I’ll run that test tonight, Gary! Thanks again! I owe you at least a donut.

1983 Bronco 4.9 300 I6
Current Name: Whitney

Gary Lewis

Re: Not a fuel issue?

Administrator

LOL! Proper subjecting? What's that?

Truthfully though, there's no "right" on how to use threads. My philosophy has been to keep almost everything about Big Blue's transformation in that thread so I can search just that thread to find what I'm looking for. But that has problems as many people have grown tired of such a long thread that they no longer even read the posts.

So on one-off items that may be more general in nature I may start another thread briefly, but tie it back to the main thread. For instance, fuel delivery modules. I wanted a larger audience to see that one, so started a new thread. But when I'd gotten to a point I jumped back to the main thread.

Meanwhile, back at the ranch, you may be resolving problems introduced while they tried to fix problems induced by the fuel system grunge and air leak.

As for the doughnut, as long as it comes from a little shop on a weird corner with almost no parking I'm in!

Gary, AKA "Gary fellow": Profile

FrazerJames

Re: Not a fuel issue?

In reply to this post by Gary Lewis

Ok Gary - here’s the weird part. I pulled off the air filter and the choke is stuck OPEN. That said, I did lower the idle a half turn (I contacted the PO and he says he’d been messing with it) and it started right up and stay smooth with the air filter off.

But the choke remained open. Here’s some video of it. Here it’s been only running for about 10 seconds. Still stone cold. For some bonus footage, I’m still getting bubbling in the filter...

1983 Bronco 4.9 300 I6
Current Name: Whitney

FrazerJames

Re: Not a fuel issue?

Also, I’ve never worked with a carb before - I expected there to be some springiness to the choke? I can close it by hand and it doesn’t move.

1983 Bronco 4.9 300 I6
Current Name: Whitney

Gary Lewis

Re: Not a fuel issue?

Administrator

In reply to this post by FrazerJames

If the choke has no spring to it then it isn't set up correctly. When the engine is cold and you slightly open the throttle the bimetallic spring should close the choke to within ~1/8" of being fully closed. And it will be held there by spring pressure.

As the bimetallic spring warms up it slowly uncoils and causes the choke to open until it will stand straight up and down. And, it will be held there by some spring tension.

But you say the engine is now running well at idle? Have you tried to drive it yet?

EDIT: I forgot the filter. I've seen bubbling in filters on most trucks, and I don't know why. So if yours runs right I wouldn't worry about it.

Gary, AKA "Gary fellow": Profile

FrazerJames

Re: Not a fuel issue?

I haven’t tried driving it yet, no. I’ll give it a shot tonight. That was my understanding of the choke so I thought it was weird. I’ll see if I can figure out where it may not be connected correctly.

1983 Bronco 4.9 300 I6
Current Name: Whitney

FrazerJames

Re: Not a fuel issue?

It looks like I have the Motorcraft 7700 carb. Came accross this in documentation. Sounds like no spring?

1983 Bronco 4.9 300 I6
Current Name: Whitney

old55pete

Re: Not a fuel issue?

Just a question? Have you put a fuel pressure guage between the fuel pump and the carb? If memory serves, it should be between 5 or 6 lbs of pressure with the engine running.

Another thing you might want to do is to look down the throat of the carb and, by hand, quickly open the throtal linkage and see if there is two sprays of gas coming from the bowl side of the carb. Do it several times. If the spray quits after a couple of pumps then the bowl is empty then the float in the carb or the needle valve may be stuck.

If I understand correctly, it sat for several years with bad gas in it, that being the case, it might be time to rebuild the carb.

Steve
86 Bronco, XLT, 5.0 EFI, EEC IV, AOD, IFS, limited slip front and rear, 3.08 gears, Tilt steering, factory AC

FrazerJames

Re: Not a fuel issue?

Thanks!

I’m definitely getting good pressure in the throat. In fact, I just took a test drive to get her up to temperature. And I’m definitely idling wayyyyy too high. I can hit 25-30mph without stepping on the gas on a flat street. The weird part is that I have the idle (or what I think is the idle adjuster) all the way down. I think with the throttle wide open all the time it’s just sucking in too much oxygen. I’d call it running “rough.”

Ran her a good 10 minutes and opened up the hood after turning the engine off. I had some smoke coming out an open tube. Not sure what it is, but I’m guessing it had something to do with the EGR that was removed by the PO. Video below.

I really think the carb just wasn’t put together correctly. It’s missing spring action for sure. I do want to eventually move to EFI - maybe I should just run with that at this point.

1983 Bronco 4.9 300 I6
Current Name: Whitney

Gary Lewis

Re: Not a fuel issue?

Administrator

The 4.9 never came with the VV. You should have the Carter YFA.

If the choke isn't controlled by a spring then remove the black cover and the problem is probably in there.

And if you are idling high with the idle screw backed out then you have a vacuum leak. A hose may be off, the carb may be loose on the manifold, or you may have a cracked line. But a high idle is the result of a vacuum leak.

Gary, AKA "Gary fellow": Profile

FrazerJames

Re: Not a fuel issue?

Maybe it was changed at some point? It’s got this tag. I can’t find that number referenced anywhere.

1983 Bronco 4.9 300 I6
Current Name: Whitney

Gary Lewis

Re: Not a fuel issue?

Administrator

The carb shown in your pictures and videos is the Carter YFA. There's a pic of the VV below, and it is a very different, and unusual carb. You can see our documentation on the YFA here: http://www.garysgaragemahal.com/carter-yfa-1bbl.html

But I'm having trouble reading the tag. It looks like it says E5PE and then there appear to be two or three characters after that, before the 772 on the next line. I find plenty of E5PE carbs, but need the characters after that to nail it down.

Gary, AKA "Gary fellow": Profile

old55pete

Re: Not a fuel issue?

In reply to this post by FrazerJames

That tube that has the smoke coming out of it is part of the vacume tree, In the video, there seams to be several missing vacume lines. That in it's self will make the idle high. Is there even a vacume hose to the vacume advance on the distrubuter?

Steve
86 Bronco, XLT, 5.0 EFI, EEC IV, AOD, IFS, limited slip front and rear, 3.08 gears, Tilt steering, factory AC

FrazerJames

Re: Not a fuel issue?

In reply to this post by Gary Lewis

Gary those last letters are MA

I did figure out it was a carter after digging around the documentation after. Thanks for that suggestion.

As far as the vacuum, I really won’t be able to dig into that until next week (I left for vacay today). I know the PO had the EGR removed. Not sure if that is tied to that or not...

Either way, I think I’m going to go EFI at this point. If I’m going to have to do work on the carb I’d rather just use the time to move to that.

1983 Bronco 4.9 300 I6
Current Name: Whitney