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Gas leak, occasional power loss

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81f100custom

Re: Gas leak, occasional power loss

Good to hear you got it fixed. I was there once myself and even had the truck towed before figuring out it was the line from the sending unit to the frame that had just deteriorated on the top side open to atmosphere and was sucking air.

Eddie,
81 F100 Custom SWB, 5.0L, 4x2, Single Rail Four-Speed Overdrive, 3.00 Non-Limited Slip Rear Axle, Non A/C truck to complete 85 F150 factory A/C conversion, Nutmeg interior color.

JG2020

Re: Gas leak, occasional power loss

In reply to this post by Machspeed

Of course! It was Gary's solution. It's crazy how the line did not leak gas but I could blow air right through it with my finger pressed on the other end. If anyone can chime in on my spark plug pics and condition that would be great. I ordered a new set and will put them in tomorrow. If they just look rich I will have to look into the carb more in depth , but if it looks like oil blow by I may have to get hotter plugs and just live with it.

Thanks!! Great group.

Josh G
1984 F-150 Inline-Six 300

Gary Lewis

Re: Gas leak, occasional power loss

Administrator

I don't think the rubber hose on Bullnose trucks was every expected to carry ethanol, and I suspect that is what is causing the problems with them. But I'm glad you got it fixed.

On the plugs, your pic looked very dark so I've made it lighter as well as bigger. And the plugs show either a very rich condition or oil being burned. Are you using any oil at all? If not, I think your air/fuel mix is too rich.

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

ArdWrknTrk

Re: Gas leak, occasional power loss

Administrator

Josh, I think your truck is running rich on idle.
Grey or black is fuel.

Blue haze is more typical of oil.(also more common on startup and trailing throttle)
The plug threads dont look lubricated like they would if there was oil in the cylinders.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

JG2020

Re: Gas leak, occasional power loss

Thanks all ! I will check the oil but only a few hundred miles since the last change. When I turn the idle screw all the way in it doesn’t stumble or die. It runs better.

I don’t see blue smoke really and not when at speed or if I pound on the accelerator . I have been watching for that when I drive.

Josh G
1984 F-150 Inline-Six 300

Gary Lewis

Re: Gas leak, occasional power loss

Administrator

If it runs better with the idle mix screw turned all the way in then you have a problem. And I'll guess it is the accelerator pump that's leaking.

If everything is working correctly you should be able to get max idle speed with the idle screw open a turn or two. That means you don't have either fuel leaks or air/vacuum leaks. But in your case something is leaking fuel, and about all that can leak fuel on a Carter like that is the accelerator pump.

And that is why your plugs are so dark. And probably why you see smoke at idle.

Gary, AKA "Gary fellow": Profile

JG2020

Re: Gas leak, occasional power loss

Thanks Gary , from my vw days that is a diaphragm made of rubber or the like ? The carb was rebuilt but for all I know it was sitting on a shelf for 10 years and that could have rotted .

I guess I am taking the carb out !

Josh G
1984 F-150 Inline-Six 300

Gary Lewis

Re: Gas leak, occasional power loss

Administrator

I'm not au fait with that carb. But we have lots of documentation on it: Documentation/Fuel Systems/ CARBURETORS, CHOKES, & EFI/Carter YFA 1BBL. There's the factory shop manual section as well as a document from Walker on the Instructions tab. (Unfortunately the Exploded Views & Part #'s tab isn't working, so I need to figure that out and fix it.)

Also, Bill Vose/85lebaront2, our resident fuel system and ignition expert has written a "Tips" section. And the very first statement in the tips is "The Carter YFA is a fairly simple carburetor, which has one major weak point - the combination accelerator pump and metering rod control. This is a diaphragm with manifold vacuum on bottom and fuel on the top side. When this diaphragm fails the fuel is drawn directly into the intake."

And I'm pretty sure that's what the problem is with yours. So I do think you'll have to pull it off and go through it.

Gary, AKA "Gary fellow": Profile

JG2020

Re: Gas leak, occasional power loss

Thank for all that info Gary! I took the carb off today so I can rebuild it in the basement tomorrow while we get hit with the rain from Ida. A not that tiny amount of anti freeze leaked out from the bottom of the carb mount stand which I know I should replace . Here are some photos. Not sure what the heck is with the goop on the water hoses . There was also antifreeze in the exhaust manifold. Not sure if that was there before I took the carb off.

Thanks ,
Josh

Josh G
1984 F-150 Inline-Six 300

ArdWrknTrk

Re: Gas leak, occasional power loss

Administrator

Aren't we looking down into the intake manifold?

Odd collection of galvanized plumbing elbows slathered in what looks like RTV.
I'm guessing that is a heated base plate to help atomize fuel in cold weather.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

JG2020

Re: Gas leak, occasional power loss

Whooops ! Sorry , yes intake . The antifreeze is normal ? I have seen the carb mounting stands to eliminate the old base I guess was used with the old feedback carb? But the one I saw was $100 at the time

Thx !

Josh G
1984 F-150 Inline-Six 300

Gary Lewis

Re: Gas leak, occasional power loss

Administrator

In reply to this post by ArdWrknTrk

Jim - I think you are right. But I don't think there should be coolant leaking when the carb is pulled.

Is that hole with coolant in it supposed to be sealed?

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: Gas leak, occasional power loss

Administrator

I think that hole is for the EGR spacer to connect to, but I can't be sure.

I'm no 300 expert and it's hard to grasp what I'm looking at with only close-ups and pics sideways.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: Gas leak, occasional power loss

Administrator

I agree. I've worked on David's 300, but only once and it was just for timing and AFR. So I don't know how to help.

I'm going to tag Dave/FuzzFace2 as I think he will know.

Gary, AKA "Gary fellow": Profile

JG2020

Re: Gas leak, occasional power loss

Thanks guys! It did not look right to me and the little puddle inside the intake was concerning. Maybe the gasket is supposed to block that hole?

Josh G
1984 F-150 Inline-Six 300

Gary Lewis

Re: Gas leak, occasional power loss

Administrator

I was wondering if it was expected to plug that hole. But if I remember correctly Dave said he used a brass cup plug to seal that hole. Let's see what he says.

Gary, AKA "Gary fellow": Profile

JG2020

Re: Gas leak, occasional power loss

Sorry for the cr***y pics . I will get some better ones of this Frankenstein setup.

Josh G
1984 F-150 Inline-Six 300

FuzzFace2

Re: Gas leak, occasional power loss

In reply to this post by Gary Lewis

Dave is in the house!

Ok from what I can see he is running EFI exh. manifolds and has a hot water heating plate bolted to the bottom of the intake where the log exh. manifold was bolted to.
If that is the case I was afraid of that happening or the gasket not sealing and the intake sucking coolant in and think a head gasket went bad.

If you were to look over the intake and where the plate is bolted to, coolant will make it up to that point.
My fix for that and now happy I did this, was to install a freeze plug with a little sealer on it.

I have had may carb off a time or 2 and had no coolant leak so guess it is holding.

As for the idle mix screw not doing much what was the idle speed set to?
If it was to high the mixture screw would not do much.
I dont know if the accel pump could cause a rich idle on the Carter carb?
It sits in the bottom of the float bowl and there is a plastic tube that goes from the pump body to the carb body and the passage for the discharge into the carb.

If the pump is bad the rebuild should fix it.
Dave ----

Dave G.
81 F100 flare side 300 six / AA OD / NP435 / 2.75 gear
http://cars.grantskingdom1.com/index.php/1980-Ford-F100?page=1
81 F100 style side 300 six/SROD parts truck -RIP
http://cars.grantskingdom1.com/index.php/1981-Ford-F100

ArdWrknTrk

Re: Gas leak, occasional power loss

Administrator

In reply to this post by JG2020

That wasn't meant as a criticism of your pictures.
Just that my lack of familiarity with the 300 makes me question context and what all I don't see...

Perhaps Dave, David, Larry or someone else with a 300 has better answers for you.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

ArdWrknTrk

Re: Gas leak, occasional power loss

Administrator

And just like that.....

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

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