Carburator Problem

[redneckdan]

Is anyone else here a trucker tinkerer? I'm having problems with the motorcraft 2150 on my 351W. It runs okay without a load. But when I let the clutch out and start giving it gas, it sputters and coughs, little to no power. Any ideas? I tried adjusting the float level but it made no differnece. It ran kinda rough so I replaced the needle and seat, now it barely runs at all.

[StarMetal]

Get a Chevy....no just kidding. Best thing to do is take the carb off and tear it totally apart and get you a gallon of that carb cleaner and soak it good, rinse, then blow it out with air. Watch your eyes. Presumebly you bought a rebuild kit. Then put it back together following the instructions on the kit. I use to rebuilt my carbs periodically, was a great tune up. Sounds like you have a fuel passage plugged somewheres.

Joe

[keeper89]

Just a couple of cents here from someone who has done the rebuild thing once or twice--take your time and make sure that everything is clean--really, really clean. And don't try to force anything on reassembly, go slow and follow the instructions that come with the rebuild kit and you should be ok.....good luck!

[walltube]

Are you certain it's a fuel system problem? Have you looked down into the carb with choke open to see if the accelerator pumps are 'squirting' as you work the throttle linkage? Fuel pump maybe? Filters? The rubber hose from fuel pump inlet\supply metal tube to fuel tank may be rotten and sucking air.

If all the preceeding is o.k., I suggest you look into the dirty little sneak that lives inside a Ford distributor: better known as the magnetic pick-up trigger. They are usually blue in color and then die a light tan. These critters and the module bolted to the inside left fender of your truck conspire to drive a good man insane enough to buy a Chevy in a fit of madness.

So, you're a Foad man, right? Me too till my Bronco drowned :violin:

Good luck. Keep us up to date with your progress.

Regards,

W'tube

[redneckdan]

i just went out and checked the carb mounting bolts and they were loose. Tightend them down and I'm gonna try readjusting the float tomorrow. I did try oerperating the throttle linkage and the accelerator pumps are working. I'll check the distributor tomorrow. I also have a couple of spare brain boxes but I've heard when they go bad that the engine will not run period.

[StarMetal]

Redneck,

While you're at it check the action bolts on your rifles too. [smilie=1::kidding:

Joe

[walltube]

i just went out and checked the carb mounting bolts and they were loose. Tightend them down and I'm gonna try readjusting the float tomorrow. I did try oerperating the throttle linkage and the accelerator pumps are working. I'll check the distributor tomorrow. I also have a couple of spare brain boxes but I've heard when they go bad that the engine will not run period.

You are right about those branes. Without disconnecting the plug-ins unbolt the module from the fender turn it down side up and take a look at the epoxy insulation. If the epoxy is smooth and firm to the touch most likely it is still in good working order. On the other hand if there is any of the insulation melted away and some run onto the fender, or if it is soft and sticky like, throw it away. This is an indicator of over heating sometimes brought on by having the ignition key 'on' for an extented time w\o engine running. The reluctor(that gear looking dealie) inside the dist. when lined up with the mag. pick up is sigaling the module to be 'on'. It's working its' little heart out to obey the "fire" signal to the coil.

A tour through a Summit cataloge's ignition section will put you in touch with yer trucks desire to give you better than stock performance with increased fuel economy. You must know Summit don't you? :)

I miss my low-tech 1980 Bronco. Sigh.

W'tube

[454PB]

Did you change the fuel filter?

[Four Fingers of Death]

I had similar symptoms with a Landrover some years ago. I thought fuel, but 100miles from home and the only mechanic I know saw me and pulled over. He had a bit of a squiz and told me to replace the condensor. I had spare everything in the truck and was burning up the highway (well as fast as you can in a stock Landrover) 5 mins later. Mick.

[David R]

I went to college and they told me then that most carburator problems are in the distributor. They are correct.

Do you have good spark? Under load is when weak spark will give out. Some times its just the plug wires. Fords coils also tend to "wear out".

If you take a spark plug and open the gap to about 1/4 inch or quite a ways, put it on the Distributor end of the coil wire. Crank it over. The spark should be BLUE Duraspark II should jump more than 1/4" easy. Newer electronic ignition will jump 3/4 inch.

If it has good spark from the coil wire, check it at the plug wires. Spray the wires with water while the engine is running. Watch for arking or rough running. Does it run worse in the rain? Is the spark plug gap correct? Is says what it should be on the white long sticker under the hood some where.

Don't replace anything until you are sure what is giving the trouble.

Spark plug wires should have about 10,000 ohms per foot.

I have been a mechanic longer than I have been casting boolits.

Good luck
David

[David R]

Sunoco gas has 10% ethenol around here. If you use that, you will never need dry gas.

David

[sundog]

Did the problem start like 'right now' or did performance deteriorate over time?

I'd be checking spark like others said. Also, vacuum advance. And, look really, really good at the float. Any pin holes? Look at the inside of the distributor cap. I di a tune up once on my ole 68 Fury and went through at least 3 caps in as many days until I got one that wasn't all spider web cracked on the inside. sundog

[redneckdan]

It had been running kinda rough and I figured it was caused by a worn needle and seat. So I replaced them and also added a new fuel filter. After class today I'm gonna go through the check list you guys gave me and see what I can find.

[redneckdan]

come to think of it, last time it rained it did not run right until it had warmed up and dried out.

[StarMetal]

Redneck,

Just rebuild the carb. Then go from there. Rough running normally is that something is wrong with the fuel mixture, providing the engine is good shape.

Joe

[Bigscot]

I was having problems with my truck a while back. On damp mornings it might be hard to start and once started would idle fine but would bog down when pressing the gas and run rough. Later in the day everything was fine.

I finally changed out the distributor cap and rotor button and the problem was solved. The truck has been running like a champ since.

Bigscot

[walltube]

G'Morning Dan,

If after you've rebuilt the carb as Starmetal has said and all is still not well, I'd lay my money on ignition and other under the hood electric demons.

Let's start with the distributor cap:
Moisture INSIDE the cap is not an unusual occurance. Water will promote high amperage 'spark jump' from one internal spark plug terminal to another as the rotor clocks its' way from terminal to terminal. This causes a premature and\or late firing order. Evidence of this is the "spider web" looking tracks on the inner surface of the dist. cap. This is called carbon tracking. It etches the plastic cap and is not easily cured. An ever present cloud of hydrocarbons under the hood make their way into the cap. An unholy union of elements.

Aluminium terminals are quickly eroded and add to this mess by the vapourised aluminium also being deposited along its' own path. In short (no pun intended) what you have is a miniature, uncontrolled lightening storm destroying the cap innards and engine performance. Toss the OEM cap for an aftermarket epoxy "Accel" brand cap with brass terminals and likewise rotor.

Plug wires:
Carbon core OEM resistor type plug wires will deterioate slowly but surely. As the carbon core breaks down it increases resistance to the electric pulse traveling on its' way to the plug. This condition causes the 'juice' to back up into the dist. cap not unlike a dammed stream, further adding to the dist. cap woes. As mentioned by other posters here the plug wires will succumb to age and the ofttimes harsh under hood environment. The outer coating loses its' insulating properties. Cracks develop allowing moisture and the ever present hydrocarbons to disrupt the controlled flow of juice to the plugs. Also said here is to witness the lovely electric light show that are a positive sign the wires are a leaking. Toss the OEM wires for a better quality aftermaret performance set.

In hopes I've been of some help to ya, I wish your Ford a speedy recovery :)

W'tube

[StarMetal]

Walltube is right. You know there are three things to making your engine run, fuel, air, and ignition. That's providing the engine itself is in good mechanical condition. With rebuilding the carb, which sounds like it needed it anyways, and by replacing the fuel filter, which you done, you pretty much eliminated the fuel/air section. That's two of the three. Now you're onto ignition which covers ALOT of stuff, which walltube and others have mentioned. I hate to say this but if you found your carb bolts loose it sounds like you neglect your engine, car even. Sorry, I grew up a motorhead and I try to take care of my car and it has paid off for me too.

Joe

[redneckdan]

the carb was swapped out before I drove up to college. Just recently checked the bolts. THey weren't rattling loose but they weren't as tight as they should have been either. I definitely don't neglect my vehicle.

[StarMetal]

Well I didn't mean to offend you. Do let us know what you find.

Joe

[redneckdan]

i went and checked the dist. cap and the plugs. Plugs do look worn so I'm gonna go get a new set. The dist cap looks like brand new inside, no spider tracking. The plugs were quite sooty but not oil fouled, I beleive it has been running rich for a while.

[StarMetal]

Fluffy flat black soot is over rich. Wet black is burning oil, can also be burning oil and overrich. I think with the carb rebuild and new plugs you should be fine. You mentioned the carb was swapped out, why?

Joe

[redneckdan]

FOUND IT!! The brake booster is leaking. Undid the vacuum line, folded it over and zip tied it. Runs like a champ, stoipping is another mattter....

The old carb would flood out and then run lean. Every time I opened up the float bowl, I would find sand inside it. Still have it and plan to take it apart to find out why. I think the sand got in there when the previous owner rebuilt the engine in a friends barn. The rebuild took place in a clean shop but the truck and rest of the parts stayed in the barn. Said friend has cats and I assume said cats would climb over the carb and sand from their feet would get into the carb....at least thats my theory. Thanks all ya'll fer yer help.

[keeper89]

Just glad you're out of the woods--hard to see through all those damn trees sometimes---:drinks:

[walltube]

Hello Dan,

Starmetal is right on with the fuel\air mixture advise. A vacuum leak of the proportion you describe will upset any carbs f\a mixture adjustments.

However, sooty plugs are not always indicative of a too rich mixture. When an engine has many miles; loss of compression w\o oil fouling; a hotter plug range may be the answer. Also low speed stop and go driving will contribute to this condition.

Dan, did you not notice any increased pedal resistance from usual as you applied the brakes? When the diaphram fails it cannot provide the assistance needed to make 'Power Brakes' power brakes. Hence a "hard" pedal. I suggest you change the one way check valve first. They are much less expensive and far easier to replace than the booster assembly. IMHuO.

Good news on the healthy dist. cap. At least you won't have to spring for the $$.$$ to buy a new one. Post more updates.

W'tube

[slughammer]

FOUND IT!! The brake booster is leaking. Undid the vacuum line, folded it over and zip tied it. Runs like a champ, stoipping is another mattter....

If you are going to buy new, I recommend calling all the convenient parts stores around for prices first. I bought a new Raybestos for $70 less than if I hadn't taken 10 minutes and called around.

[redneckdan]

the engine was completely rebuilt about 2000 miles ago. I plan to do a compression check pretty soon here. I called auto value and napa and they quoted 110 and they have to wait 2 days for it to come in.

[StarMetal]

redneck,

the reason you do a compression test is to see if your rings seated properly, if the valves are making a good seal in the valve seats, and if the headgasket is leaking. Do you suspect one of those three things are happening?

Joe

[redneckdan]

I don't suspect any of those but I would like to have a measurement that I can compare future measurements to.

[sundog]

Dan, glad you've apparently found the problem. One of the best diagnostics tools on carbbed motors is the vacuum guage - not just testing when idling, but left connedted while driving. Vacuum leaks can drive ya nuts. sundog

[felix]

Tell me about it!, Sundog. These leaks appear out of nowhere whenever the car/truck is driven on "rough" roads, or on city streets which try to flex performance suspensions. Also, havta' check quite often for loose wires because of the same reason. Did I ever mention that cars and I don't get along? ... felix

[walltube]

Dan,

Rebuilt 2000 mi. ago? Aw shucks, that's no fun! Only engines with over 150,000 mi. are interesting.

If you haven't noticed yet, us old motorheads (like me & old Joe :) ) are like a bunch of grandfathers fussing over the g'kids gun that won't shoot "straight" or fishing rig that refuses to 'catch'. We just can't help ourselves, it's our place in the universe. Been that way since Adam. Some Ya'll out there know what I'm talking about, don't you? ;)

And you're paying HOW MUCH for a new brake booster!? AAAUUUUGH!!! I've never paid over $20.00 at a salvage yard. :)

Best to you, Dan.

W'tube

[redneckdan]

I haven't ordered it yet. Not exactly in the budget at the moment. I only need the truck for bow huntin (ie trail driving) right now so I can get away with manual brakes for the moment. I thought that brake boosters were a part that you shouldn't get from a junk yard? Doesn't the diaphram deteriorate when it sits unused?

[walltube]

This is a bit over simplified (I do simple real good), but for the purposes of answering your question:

When the brake pedal is released and allowed to return to the 'up' position the diaphram sucks in the surrounding atmosphere to fill the previous vacuum void within the booster "can".

Ozone, hydrocarbons and leaking brake fluids (however minute) mix with the incoming air to break down the diaphram's material of which it is made. Of course age & use play their part too.

All this was told to me by an aftermarket manufacturer to wannabe parts re-builders like me. Oh yeah, thought I'd make a fortune re-building all that junk. Two lectures later and I went back to being a weldor. [smilie=1:

Anyway, Dan, I don't think that prize 12 point buck piled up in the bed of your Ford truck will give damn what condition the brakes are in.

Good Hunting,

W'tube

[redneckdan]

I agree with ya. I too find welding to be much simpler, even unbalanced wave TIG.

[SharpsShooter]

Rebuilt 2000 mi. ago? Aw shucks, that's no fun! Only engines with over 150,000 mi. are interesting.



You would love my 86 Jeep Wagoneer Limited..........259,800 miles and while it runs fantastic:-D , the tranny started slipping a few weeks ago:neutral: . I can't decide if it is worth the expense of a remanufactured transmission or not.


SS

[David R]

Get a booster from a scrap yard, don't drive around with out it, then wish you had bought one. Its not worth the risk.

Glad you found it

David

[walltube]

Dan,

I like(d) TIG too. As a matter of fact, I liked TIG so much I temporarily purloined a Miller welder after my retirement just to keep my hand in it fabbing smokers, BBQ pits, etc. Much more fun than a pipe hi-line or nasty old boiler. Or a stinking refinery.

SS,

Buy the Wagoneer new? 259,000 mi., that almost qualifies as a love affair :)

A pre-Iacoca American Motors Wagoneer, right? 360, 390, or 4?? engine? IIRC, that's a Chysler 727 tranny behind the engine. Wow, I gotta stop taxing my memory, I feel a headache coming on. :confused:

W'tube