how does older carb work? mine won't stay running.

[canucklehead]

I took apart and cleaned carb on my '62 IH B414. I was able to clean the jets and got good carb cleaner spray and blew air through them. My problem is fuel flow. I can dump gas in through carb and tractor will run. The moment I stop feeding it fuel, it sputters and dies.

There is a large butterfly valve on top of carb controlled by a choke cable. no problem, that works.

There is a second, smaller butterly valve controlled by the throttle cable. This is where I think my issue is. This valve would not fully open. It has a rod/lever connected to something inside the float bowl. I'm guessing that lever is connected to the accelerator pump (but could be out to lunch on my guess). Whatever that rod connects to is seized. So I banged on what I'm calling the accelerator pump and got it down deeper inside float bowl. Now I can at least see the smaller butterfly valve open and close when I move the throttle cable. But the "accelerator pump" is still not moving and is now stuck in a down position. I suspect it is supposed to slide up and down freely with the rod connected to the valve.

So would this seized part cause me to have no fuel flow? Anywhere I can buy a new float bowl and "accelerator pump" ?

I loosened the fuel line fitting at the carb and cranked engine and fuel seemed to flow well from the fuel pump to the carb.

One other possibility (doubtful)...... when I pulled off the float "needle" flap (it's not a needle, it's a flap), I didn't pay close enough attention to which way it sat. The flap says "top" and I positioned it so "top" was facing up (as in I can read "up" when the flap sits on top of float bowl), so i think I got that part correct. I think when the float raises this flap pushes on the needle to stop gas from overflowing into float bowl (??). Anyways.... possibly i got this upside down or incorrectly installed and needle isn't opening to let fuel in (??).

 

[NormL]

If you post some pictures of your carb someone on here may be able to guide you. You don't say anything about the carb running over. If you had, that might mean the float was stuck low in the bowl. How about when you open the carb up again. Is there evidence of fuel present? If not, then try tracking down the problem from that angle.

 

[canucklehead]

thanks NormL. I will remove it and take some pics in the next couple of weeks. I found someone else that seemed to have similar problems. I believe they called it the accelerator pump valve. Not sure if being seized, I'll have to remove it in order for it to run.

If I put the float needle flap in upside down, i think fuel would overfill and leak out. It wasn't doing that. It also wasn't getting enough fuel to run. I couldn't get part of the carb apart (2 slot screws hold the jet assembly in place). I got one to break free and I could tell I'd strip the second screw if i kept working it.

So what's a good product to soak this in for a few days to try and free up some of these seized pieces?

 

[jab-law]

I actually sounds like you are not getting enough vacuum. It that case, the carburetor itself may not be the problem, but the vacuum may have a leak. Check to make sure that all the vacuum hoses to the carburetor are hooked up, and that they are not cracked. also, you should check the gasket around the base of the carburetor. While the carburetor itself may still be the problem, getting the vacuum leaks issue checked will ensure that you are getting enough air pressure through the carburetor (venturi effect).

 

[canucklehead]

i didn't notice a single vacuum hose. There is a fuel pump to get fuel there at the banjo bolt.

wondering if the "accelerator pump" off the throttle cable does the same thing as vacuum would do (?)...like pump fuel?

 

[canucklehead]

I am going to post 8 pics in 2 posts.
The first 2 pics are of the 2 different sides.


notice the rod going into the float bowl on pics 2 & 3 . i think this is for accelerator pump.




pics 4 & 5 are the float bowl. Notice the groove, and one end has an indent/concave, the other side is more convex. so which end is up, and which is down on this float bowl?

 

[canucklehead]

here are the last 3 pics. this isn't a very clear pic but it should give the idea. This is the flat float flap that gets pushed against the needle. It is sitting on top of the float. I was trying to get a good macro shot of the word "top" on the flap. So "top" is facing up towards me taking a picture. I assume that this is in the correct position. It can be flipped to sit the other way (maybe the word "top" faces the float, and not facing up towards me????)


side view of the float bowl. 2 screws hold a block against the inside of the float bowl (next pic will show this "block" better). The jets are mounted on this block . You can see one screw is getting close to stripped. Can I use an impact driver on this, or will I destroy float bowl? I'd like to remove that block to clean it up better.



okay, lots of info in this pic!! the block has the big brass jet on it. To the left is the accelerator pump valve/plunger. You can see the top is a bit shiny and mangled from me trying to pull it off with needle nose vice grips. Not sure what I can do to free this up/remove/clean it. I smacked it downward into the channel it sits in, so at least the throttle valve will open and close, but this plunger doesn't move. I am soaking the entire float bowl in diesel fuel (recommended by my cousin). i also have solvent but he thought diesel would work better. Any thoughts?

 

[canucklehead]

this is a Zenith VN carb. i noticed B64 stamped, and I also saw letters that looked like C1836 or C1886.

 

[NELS1]

The accelertor ppump has to move freely up and down and on older equipment usually made of leather rather than neoprene .
As the name suggests it pumps ( Squirts ) extra fuel into the carb on acceleration. The float sits at the bottom of the float bowl and allows fuel to fill the bowl assembly until it raises and shuts off the fuel supply by pushing the needle or flap over the hole the fuel comes in. Look inside your toilet to see exactly how the float works. Same principal.

 

[Leejohn]

here are the last 3 pics. this isn't a very clear pic but it should give the idea. This is the flat float flap that gets pushed against the needle. It is sitting on top of the float. I was trying to get a good macro shot of the word "top" on the flap. So "top" is facing up towards me taking a picture. I assume that this is in the correct position. It can be flipped to sit the other way (maybe the word "top" faces the float, and not facing up towards me????)


side view of the float bowl. 2 screws hold a block against the inside of the float bowl (next pic will show this "block" better). The jets are mounted on this block . You can see one screw is getting close to stripped. Can I use an impact driver on this, or will I destroy float bowl? I'd like to remove that block to clean it up better.



okay, lots of info in this pic!! the block has the big brass jet on it. To the left is the accelerator pump valve/plunger. You can see the top is a bit shiny and mangled from me trying to pull it off with needle nose vice grips. Not sure what I can do to free this up/remove/clean it. I smacked it downward into the channel it sits in, so at least the throttle valve will open and close, but this plunger doesn't move. I am soaking the entire float bowl in diesel fuel (recommended by my cousin). i also have solvent but he thought diesel would work better. Any thoughts?

!st pictures isn't clear as you said, to me it looks like the lever that shuts off the needle is up side down. It looks like it could dig into the float.

 

[canucklehead]

I found a Zenith VN carb diagram. I have the "float arm pivot assembly" (flap) positioned correctly. And the groove on the float should be at the bottom.

I was close on describing the "block". Zenith calls it "emulsion block" On the bottom/underside of that emulsion block is a mainjet and a compensating jet. The 2 brass jets I removed (there are 2 stacked on top of one another on the top of emulsion block) are essentially pilot jets.

They call the accelerator pump that is stuck "pump piston". There is also a pump spring under it, and a pump check valve.

Even if this pump gives a squirt on acceleration, if all the jets were working I should still be able to run without manually dumping in fuel. I think the jets on the underside of the block may be plugged up.

So folks, what's the best product to soak in to free up these stuck pieces, and to give me a chance to remove that emulsion block screw? can I use mild heat on that screw to help persuade it? Impact driver?

 

[DFB]

Sounds like you got it figured out what you need to do.

The Zenith/Bendix on my old Harley operates similar and also has the accelerator pump which as described earlier gives that xtra fuel when the throttle moves. If your float bowl is filling up with gas (and not overflowing) the float is asy probably works ok and its still more than likely you have a plugged jet circuit especially if it runs when you put additional gas into the venturi. When solvents and compressed air wont clear a jet it helps to have a wire tool like this Carb-Cleaner-Wire-Set. Others use a similar tool made for cleaning welding tips.

On that stuck screw best bet is a soak with a penetrating fluid. Kroil is one of best you can get. PB blaster works for me too and really good tight fitting screwdriver tip. A little impact never hurts.

 

[canucklehead]

unfortunately the main jets are on the bottom of this emulsion block so I can't get at them until I remove the block. I'm guessing they get the bottom sludge first as it seems to settle lower in float bowl.

another guy told me he drilled out bottom of float bowl cylinder area where the accelerator piston goes up/down, tapped out piston, cleaned it up and then JB welded the drilled hole. He says it doesn't leak. If i can't unseize, I might try that.

 

[jimmysisson]

But not an impact driver! I'd soak it a couple days then try to tighten the screw(s) just a whisker. That often will break something loose you've been trying unsuccessfully to turn out. Even when it frees up a bit, turning out and in a bit over and over eases the strain on parts.
Those jets are prob key to good chance of running right, along withe the pump.
Good luck with the old girl.
Jim

 

[canucklehead]

I was able to remove the emulsion block. I hit the screw with one smack with impact driver (after it had soaked in diesel) and it busted loose easily.

yep, the bottom 2 jets were covered in white sludgey slime. it is scaley where it dries, and like a thick vaseline gel where it's been wetter. My theory is this is from that awful ethanol in fuel. Or does normal gas just turn into this?

the piston still won't move. Now have the piston covered with PB Blaster. If that doesn't work. I'm moving to the next snake oil= nitrolube. Actually made locally, and according to them...the best ever.

so, if i ignore accelerator pump and piston, this should still run ?? the pump just gives it a little shot of fuel when you accelerate (?). So if I don't have this, maybe I'll just have a delayed response when I throttle up....kinda like poorly tuned high/low screws on 2-stroke stuff (?)

 

[Arkaybee]

Get a gallon can of Berryman Chem-Dip; comes complete with a basket inside in which to put the parts to soak by immersing the basket and parts into the can. Close it up and let it sit for the recommended time (it may take longer than you think for those small jet passages to be cleaned).

This stuff worked really well on a motorcycle carb that was stopped-up completely.

Be sure to read the directions and precautions carefully.

HTH

Arkaybee

 

[Car Doc]

I use what I call the wire tag method on all carbs. What it is is fine wire they use on those wire tags you see attached to things. Anyway sludge etc will settle in the lower areas of a carb and cause blockage in air bleeds and fuel transfer passages.

The wire will get better for cleaning the more bends it gets in it just keep it as straight as you can, run it thru everything with a hole and blow out with air. I use Berrymans b-12 its about the best carb cleaner I know of for cleaning old varnished gas etc out. hth

You want the accel pump working it helps with starting and helps keep the engine from leaning out and backfiring when trying to speed it up. It keeps the engine from hesitating in other words.

 

[DFB]

I'm sure you can get that pump piston moving again...give the penetrating oil time to do its thing.

 

[canucklehead]

:dance1::cool2:WOO-HOO!! I finally got this stubborn BOS (dyslexia) out!! I tried PB Blkaster for 2 days, diesel fuel before that. I tried Nitrolube. I still think they're all snake oils, but who knows. Tried heating it up with propane (didn't want to try oxy/acetelyne). NOPE.. none of them did the trick. I knew I couldn't drill from bottom and push it out because there is a check valve in bottom.

so I used a lefthand easy out, the one that looks like a drill bit. First I drilled the recommneded hole size (7/64th for a #2 LH easyout). I drilled through the top of the piston. It i s soft aluminum and drills easy. Then I put in the LH easyout, used a cresent wrench to turn it and it spun, then pulled out. I used wire wheel on my bench grinder to clean up piston and a deep socket with emery cloth to try and clean cylinder area on the float bowl. I also cleaned the spring on the wire wheel.

I used a 2 part gas tank repair compound to patch the hole I drilled in the piston. First I cleaned it good with brake cleaner, as brake cleaner leaves no residue. You rub it together until it turns grey, then put it on top. I would have used JB weld if I had any, but this is what I had handy.

here is the spring cleaned up:

here is the cylinder cleaned up. I tried to remove check valve at bottom but it felt like it'd strip so I stopped. I blew air through it and used carb cleaner:


here are 2 pics of the piston cleaned up:

 

[DFB]

:thumbsup: