Got to rebuild a carb. Any tips?

[Leadfoot281]

My legendary 1983 F150 has finally given me a problem.

The other day I was hauling a load of wood with it. The mighty 300 I-6 ran just fine into the woods. On the way out, it started running really rough. Sounded like a bad vacuum leak (terrible idle) and a dead miss (maybe 3 or 4 dead cylinders). It had blue smoke that smelled strongly of unburned gas.

I pulled the cap and rotor. Both really bad. I replaced them. No change. The wires were badly cracked. I replaced them with a better set. No change.

I set the timing. Again, no change. Pulled the plugs. They were black and fouled with soot. Cleaned them. Runs better. This was when I noticed the truck burned nearly 5 gallons of gas in about 3 miles.

I believe I have an internal carb leak (powervalve/diaphram) and it needs to be rebuilt. This is a Motorcraft 1 barrel.

I'm getting the kit tomorrow. What else should I get? Parts store is 27 miles each way so I'd like to get everything at once. Got any tips?

Thanks!

[RCSignals]

My legendary 1983 F150 has finally given me a problem.

The other day I was hauling a load of wood with it. The mighty 300 I-6 ran just fine into the woods. On the way out, it started running really rough. Sounded like a bad vacuum leak (terrible idle) and a dead miss (maybe 3 or 4 dead cylinders). It had blue smoke that smelled strongly of unburned gas.

I pulled the cap and rotor. Both really bad. I replaced them. No change. The wires were badly cracked. I replaced them with a better set. No change.

I set the timing. Again, no change. Pulled the plugs. They were black and fouled with soot. Cleaned them. Runs better. This was when I noticed the truck burned nearly 5 gallons of gas in about 3 miles.

I believe I have an internal carb leak (powervalve/diaphram) and it needs to be rebuilt. This is a Motorcraft 1 barrel.

I'm getting the kit tomorrow. What else should I get? Parts store is 27 miles each way so I'd like to get everything at once. Got any tips?

Thanks!

Get a price on a rebuilt carb before you invest in a rebuild kit. Hopefully they ahve one in stock.

If you are going to rebuild it yourself get a can of carb cleaner to soak it in.
If you don't have a compressor to blow out passages get a can of compressed air. (Office or computer stores should have it)

After you've soaked it in carb cleaner you may want to boil it in a big old pot of water.

[JACook]

Get a price on a rebuilt carb before you invest in a rebuild kit. Hopefully they ahve one in stock.

NOOOOOOOOO!!!!

Sorry, but you just hit one of my biggest peeves, that being those rebuilders that think carburetors
should all get sandblasted. It's really a crime what those rebuilder mills do to carburetors.

There is no better candidate for a good rebuild than an unmolested original carburetor. Once it's
gone into the rebuild mill, it's permanently junk. It'll never work right again.

If you can find a local rebuilder that will do a proper job on the original carb, that's fine. Or a proper
rebuilt unit from the Ford dealer. But never, ever, trade it in for a McParts store rebuilt...

[jonroe]

You should also carefully check the integrity of the throttle body. Years ago I used to rebuild carburetors for cash as a teen. One Autolite 4300 4 bbl had rich running problems and it turned out to be a leaking throttle body - I mean leaking quite a bit through a bunch of hairline cracks in the aluminum straight into the intake manifold. I had to get a rebuilt carb that time. Jon

[FordNut]

I use the spray carb cleaners like Gumout. Get two cans. And as stated above, rebuild what you've got instead of exchanging it for a rebuilt one.

[JMan]

Those Motorcraft 1bbl's were notorious for leaking between the float bowl and the throttle body. Grasp it while it's still on the car and twist. If it moves it is probably loose. Screws are tightened from the bottom after removing it from the manifold. If you're gonna rebuild, work on a clean table with a border so you don't lose anything!

Good luck,

J

[Leadfoot281]

I had no intention of buying a rebuilt carb. Just for 'kicks and giggles' I asked how much one would cost...$209. Forget it! That's easily 3-4 times the value of my truck!

I bought the rebuild kit for $40 and plan on tearing it down tomorrow. Tonight I'm going to read and re-read the instructions.

[RCSignals]

NOOOOOOOOO!!!!

Sorry, but you just hit one of my biggest peeves, that being those rebuilders that think carburetors
should all get sandblasted. It's really a crime what those rebuilder mills do to carburetors.

There is no better candidate for a good rebuild than an unmolested original carburetor. Once it's
gone into the rebuild mill, it's permanently junk. It'll never work right again.

If you can find a local rebuilder that will do a proper job on the original carb, that's fine. Or a proper
rebuilt unit from the Ford dealer. But never, ever, trade it in for a McParts store rebuilt...

I would hope john would look at the rebuilt before he bought it.
Not all rebuilt carbs are bead blasted

[RCSignals]

I had no intention of buying a rebuilt carb. Just for 'kicks and giggles' I asked how much one would cost...$209. Forget it! That's easily 3-4 times the value of my truck!

I bought the rebuild kit for $40 and plan on tearing it down tomorrow. Tonight I'm going to read and re-read the instructions.

$209 is insane

[Leadfoot281]

Got the carb back on today.

Everything inside the carb was rusted and the bi-metalic spring in the choke was shot. I guess you shouldn't leave the hood open over the winter without an air cleaner. :rolleyes: I got those parts and an air cleaner assembly off a friends truck.

It started right up and ran like a new truck...for a while. About 500 feet into the road test I heard an absolutely hideous sound. I'd describe it as a bulldozer getting fed into a jet engine.

That's when I noticed the "ignition switch" was stuck forward...DOH! There isn't a key for it and I use a vice grip to start it. Apparently I hadn't pulled it back far enough to disengage the starter.

The starter spins but doesn't engage the ring gear. Guess I get to pull the starter tomorrow. This could be gruesome :lol:.

[RCSignals]

Got the carb back on today.

Everything inside the carb was rusted and the bi-metalic spring in the choke was shot. I guess you shouldn't leave the hood open over the winter without an air cleaner. :rolleyes: I got those parts and an air cleaner assembly off a friends truck.

It started right up and ran like a new truck...for a while. About 500 feet into the road test I heard an absolutely hideous sound. I'd describe it as a bulldozer getting fed into a jet engine.

That's when I noticed the "ignition switch" was stuck forward...DOH! There isn't a key for it and I use a vice grip to start it. Apparently I hadn't pulled it back far enough to disengage the starter.

The starter spins but doesn't engage the ring gear. Guess I get to pull the starter tomorrow. This could be gruesome :lol:.

While you are getting yourself a new bendix drive (or whole starter), pick up a generic ignition switch.

I hope the ring gear is still OK

[Leadfoot281]

I pulled the starter today and it's deffinately the bendix. That thing looks like it got ran through a rock crusher. The flywheel looks perfect!

I'm gonna buy a lottery ticket before my luck runs out. :D

[ImpalaSlayer]

lets see a pic of this truck sounds like a good farm beater.