The Stovebolt Site Forums The Shop Area Engine Shop Carter W-1 problems

I messed with my dual Carter W-1 set up again today. The truck runs really good once off idle and at full throttle. The problem is with the rear carb still not idling right. I have cleaned it three or four times now, studied on it and compared it to the front one, I just don't see the problem.
These are 483's.

I am down to the low speed idle jet tube being bad, it doesn't look very good and I tried to flare the end, but his had no change in idle quality.

Looking down the barrel when running, the fuel is dribbling out, you can hear each drip hit the throttle blade, the front one is mix fuel and air correctly. With just a slight choke, the rear carb perks up. I spent 2 hours turning mixture screws and idle speeds trying to find the right combination. This week I will swap front to back to verify the carbs or intake problem. Vacuum is a steady 20 inch's with the throttles open some, I don't have a full time vacuum signal except the PCV so I still need to check the vacuum at idle once I Tee into the line with my gauge.

My Uni-sinc gauge doesn't seem to be effective on these, if I set it to float the red ball, the engine will die, it needs to be at a high idle to get enough air passing through, this I believe goes back to the rear carb not acting right.

Any thoughts?

Any body sell internal parts for the W-1? I haven't found any one yet.

Joe

Joe,
Check out this site. You may find what you need. You can also email them and see if they can answer your question.

http://www.carburetor-parts.com/Carter-Carburetor_c_18.html

Harold

Thanks Harold, I had been to that site, they do sell a lot of stuff.

I found a partial rebuild kit on e-bay last night, it was very old and a original Carter kit. The low speed jet was still in the package and a few screws, for $5 I couldn't pass it up, its even listed as the right part number !

Joe

OK I am revisiting this post instead of starting a new one.

Its been almost a year since I worked on these, I put them back on today after looking at them in the basement all winter.

I installed two NOS low speed jets, flushed them out before storage, and now have them on the truck again.

I swapped carbs front to back to be sure its not a manifold problem.

I have one that will not react to the mixture screw. I can take it clear out or seat it, no difference. The carb is clearly running lean, just a slight choke will bring it on line. Full throttle or cruise is OK as far as I can tell, haven't driven to far. So today I pulled a dirty core carb out and pulled the idle circuit parts out to compare and look at. I just don't see a problem. I even pulled the small copper plugs out and ran a pipe cleaner down the holes.

I am going to pull it clear apart and give it another cleaning, All I can figure is theres a plug from the main jet, over to the idle jet.

This just can be this hard, I have rebuilt tons of carburetors and nothing has gave me more trouble then this one.

Joe

Ok, I'm suggesting you look at the problem differently.

I think your problem is a flow problem.

Remember the engine is perfectly happy idling with one carb, it will also run all the way up to full rated HP with one.

So, at idle each carb is passing only 1/2 the air through the venturi. That means the vacuum pulling the gas through the low speed jet is much lower. A very minor difference in the construction of one carb or the other can be the difference.

And yes, your Uni-sync will not work right in this case.

There are 2 things you can try:

Option 1: With the linkage between the carbs disconnected, on one, back back the throttle plate fully out so the butterfly is fully closed. Open the screw on the other to set the idle to the proper speed. Then adjust the idle mixture screw on that carb.

Now back off that throttle plate screw to fully closed, open the one on the other carb to the correct idle speed and adjust that idle mixture.

Now forget about the mixtures and open the throttle plate on the both and adjust the balance at the desired idle speed. A couple hundred rpm's above the stock idle might be a good place to go for. Use the sound of the air flow to set the balance (length of fuel hose held to the ear and over each carb. back and forth till the sound is the same).

Option 2, If you have set the air flow so the carbs are balanced and the linkage is locked together, set the idle speed to twice the factory setting. Now adjust the idle air screws. Each carb should have the air flow of an original idle and the adjustment will work as designed. NOTE: the adjustment of one one carb will only have 1/2 the effect of a one carb system so you have to listen or watch the vacuum gauge very carefully.

Good luck.

Joe - the idle circuit on the W-1 has an inverted "U" shaped passage. This passage runs up from the idle tube to a horizontal cross-over, and then down to the idle port.

Since these carburetors are cast-iron, occasionally I see one with this passage completely blocked which prevents the idle circuit from functioning, and the carb will only idle at higher RPM on the main circuit.

This circuit is accessable by removing the three copper drive plugs (1 for the vertical from the idle tube, 1 from the horizontal cross-over, and 1 from the vertical down to the idle port).

You should be able to blow compressed air through this circuit from the hole from where you removed the idle tube, and have the air exit at the idle discharge port. If not, the passage is plugged.

Jon.

Thanks guys,
JIm, the front carb will not idle, no amount of tinkering with the other or idle screws seems to help. It is just not producing an fuel at idle. The back carb responds just fine to a idle adjustment, the front one does nothing, even with the screw clear out of the hole!

Jon, I suspect the bore from the idle jet upwards. I have the copper plug out of the downward long hole and it is clear. I pulled all the plugs out of a damaged core I have last night looking to see how the fuel traveled. I figure it has to be at least at the idle jet for it run at all. After some yard work this morning, I will get back at it.

One more question Jon, where does the idle circuit get its vacuum to pull the fuel all the way up the bore and back down? Should there be a vent hole at the top of the bore from the idle jet going into the throttle bore? Seems this would let air in and not pull fuel up the through the tube, maybe its a rust hole?

Joe - there is a vent on the inside of the cast iron very close to the top.

Jon.

In your original post you stated:

"Looking down the barrel when running, the fuel is dribbling out, you can hear each drip hit the throttle blade,..."

That is not your idle ciruit acting up. The idle circuit is not visible to the eye when idling, it is below the throttleblades. What you are seeing is fuel coming from the boosters, float being too high? would be a typical cause.

to high of a float level is the biggest pain to find.best way to tell is to warm up to operating temp. then shut down motor with no air cleaners on.if you see steam float is to high and motor is sucking fuel from float bowel.best of luck with you truck

I will know later today when I get back to it if I fixed it. I removed all the copper plugs and restrictor on the idle circuit and cleaned the heck out of it. My small sandblast cabinet is filled with worn out glass beads
( mostly powder ) so I gave each bore a real good cleaning then followed up with air, strong soap, more air, and finally pipe cleaners just to be sure.
The restrictor is a very small brass plug with a .030" hole, or smaller, in the upper crosser over. I can see where it wouldn't take much to plug it up and keep the idle screw from working.

I am waiting on paint to dry so I can assemble the carb and put it back on.

I am sure the float is set right, both carbs have been check so many times now just trying to find the problem. It was dribbling fuel down the throat because the throttle was open to far, it had to be just to get it to run. It can idle on one carb, but very poorly. These are mounted to a 250 engine with a rough idle cam which makes tuning even worse. If both mixture screw do as they are suppose to, it will idle down work correctly.

I will update later,
Joe

Ok here it is, I fixed it! Man is that a relief, there must have been a clog up in the cross over bore going to the mixture screw.

It now response perfect to the mixture adjustment, the idle set right down and it actually runs really good. I have the idle at 14.0 air/fuel ratio, and is it touchy, just the smallest turn will change 1/2 a point.

The mid-range acceleration is a little lean, but other then that it runs great. The idle is much smoother then the mono-jet ever was. I am pretty happy over all.

I believe with a jetting change or metering rod change, it will be even better.

Thanks for all the idea's, and suggestions, a person can never have to many ideas.

Joe

Glad you got it fixed.

That passage is pretty small. I have seen them plugged pretty tight.

Main jet should be 0.093. With ethanol, I normally use a 0.094 jet, which pretty well takes care of the less energy in the ethanol. The 0.001 difference might take care of your mid-range lean condition.

Jon.

I went for a short drive to the recycle center to drop off some glass, truck ran really good. I had to go in and change out two of the small copper gaskets as they kept seeping where I was working, but that wasn't to big of a deal. Got ready to move the truck into the garage after setting out for a hour and could not get it to start. I held the throttle wide open till it fired up, low and behold, the rear carb is running fuel out the top.

After a quick clean up and carb removal, I find the float has taken on gas and sank. Lucky my spare carb has a decent float. The side seam split !

I haven't been out on the road yet to see whats coming next, but it did run just fine again going into the garage.

I am about ready for fuel injection or a Quadra-jet!

I am running .093" jets with 67 - 46 rods.

Joe

Joe, I have the same problem with my W-1 dripping down the throat and won't idle. The float is not bad and is adjusted correct but it is pulling fuel into that high speed venturi some how? What did you end up doing? Thanks Scott

I got the replacement float set and all is well. The truck runs really good now with dual W-1s.

These carbs seem to be dirt sensitive, I would give it a really good soaking in cleaning solvent with a new kit if you haven't done it already. Double check the float, mine had fuel inside and I could hear it when I shook it. Wasn't much, but enough to cause a flooding problem.

Joe