440 ic carb adjustment

[ironyetty]

I am having problems with my carb. I finally am putting a new float, as mine seems to keep filling with gas despite me thinking I am fixing it. Can someone tell me or refer me to instructions on how to properly adjust the power needle and idle. I have the service manuals and thought at one time I read in them about the starting point when adjusting the carb but haven't found the info since.

Thanks in advance,
Ironyetty

[JD440ICD2006]

Iron,

When you had the carb off, did you clean it? I learned the hard way (several times ) that the least little piece of trash, rust or other foreign particle anywhere in the carb will make it act crazier than my ex wife................................well, we will not go there.
It is best to unscrew each of the jets, clean them thoroughly. There is an idle jet, an econmizer jet (the smallest) and the main jet (the largest). The main jet has holes up the sides that if get plugged, the carb will not set properly.
The idle needle is the round knurl screw on top. I would start by turning it in all the way in (not tight) and then turn it out about 1 1/2 turns. Start the tractor and tweak it from there. Once it will idle, open up the throttle and adjust the load. It is the half hook near the bottom of the bowl.
Let us know how it comes out.

[CELSESSER]

Iron,

The initial idle needle setting for all TSX carbs is 2 turns off the seat. To adjust- warm the engine up and turn the throttle stop screw until the engine idles at the slow speed that you want and adjust the idle needle (small one on top of carb) until you get a smooth idle. Remember that this needle is adjusting the amount of AIR going into the idle circuit, not gas, so as you turn it out you are leaning the mixture and visa versa.
For the load adjustment(bottom of carb with the L shaped rod) the starting point is also 2 full turns but then you warm the engine up and with it running at full open throttle, turn the needle in( from the initial setting od 2 turns out) until it begins to lose power or miss, then adjust out till it runs smoothly and then turn it out the extra amount depending on the carb # EG.TSX-245, 530, and 756 it is 1/2 turn,
the 475,562,641,678,688,689,and 768 are 1 turn and the 737 is 3/4 turn after it runs smoothly. This needle is adjusting the amount of fuel so turning ti out is richening the
The float level on all these carbs is 1/4 inch and the fuel level should be 5/8 inch below the bowl gasket surface.

Hope this gives you what you need, I agree with JD440, even the smallest speck of crap will mess up your efforts to adjust properly. So if it doesn't want to run properly take it off and dissasemble, reclean and try again.

Chuck

[ironyetty]

I installed the float and had to bend it a little to keep it from overfilling the carb. I then started the machine and tried to set the idle but 1 1/2 turns out was too much I continued to screw it in until it was about 1/4 to 1/2 turn from being tight. Then I adjusted the power needle out 3 1/2 turns , this seems excessive but it was the only way it would run. It still isn't perfect as it miss's from time to time. The motor is 100% rebuilt so that should eliminate any parts of that. Any other suggestions.

Thanks in advance,
Ironyetty

[CELSESSER]

Iron,
1st- has the carb been thoroughly cleaned. Dissasembled, soaked etc?
2nd - new gaskets, throttle shaft ans seals,needle valve?
3rd- float adjusted to 1/4 inch form bowl surface (upside down with
float resting on needle valve)?
4th- you can check the fuel level in the installed carb by 1. shut off fuel
2. take out drain plug on bottom of carb 3. find a fitting that fits the
drain hole that you can hook a clear plastic hose to 4. hold the
hose up against the side of the carb and then open the fuel line.
the fuel should raise to a level that is 5/8 inch below the gasket
surface of the bowl.

If your float is set more than 1/4 inch away from the bowl surface, the fuel level is going to be low in the bowl which will make the carb run lean which is what your adjustments seem to indicate. An air leak would make it lean but if there is an small air leak you.should be able to adjust it to run well. Therefore the first two questions.
Also timing. points, condensor, coil should be thought about.

Have I missed anything anybody?

Chuck

[JD440ICD2006]

There is a finite set of rules with a carb. Learning them takes a while.
I always try to start with making sure I have reliable delivery of clean fresh fuel. I make sure that I am getting a good steady fuel flow from the tank.
As I mentioned before, there are various areas where the flow can be restricted.

1. Particles in the bottom of the fuel tank. (rust, scale, gum, dirt, and anything that somehow made it's way in to the tank).
2. Screen in the top of the fuel bowl.
3. Screen inside the inlet to the carb. (should be one made on to the end of the connector)
4. Each the three jets (load, economizer, and idle)
5. Passageways through the carb.
6. Damaged needle seat on the load needle. (comes from wear and turning too tight)
7. Damaged needle (should be smooth and uniform with no grooves)
8. Properly tuned as stated above.

Keep us posted.

[ironyetty]

I had the carb soaked for two days in solvent and the guy who rebuilt my motor also rebuilt the carb all new guts. The gas is fresh and the tank is a plastic temporary one as the original is being cleaned inside due to rust and other debris. However I am not sure about the float 1/4" adjustment I will check tonight. Thanks for all the comments and things to try, I will give a follow up based on what happens tonight.

Thanks,
Ironyetty

[JD440ICD2006]

I don't want to knock anyone's way of cleaning carbs, but I can show you debris and blockages left in a carb after many days of soaking.
Solvents will melt or dissolve gum and residues. Solvents will not dissolve rust, nor clean passages back to factory spec.
If someone claims to "rebuild" one of these and has not removed and cleaned all three jets, and cleaned all passages, it is not rebuilt.
It is more like painting a tractor and calling it "restored".
If it has been rebuilt properly, it will set properly.

The rebuild kits that have a new throttle shaft, needle & seat, and gaskets are only good if the carb is totally cleaned.
It is a hard job to rebuild one properly, could be why many only do the "soak and hope" method.
The jets have to come out if the carb will not set properly. Sometimes they have to be drilled out. This has to be done by someone that knows what they are doing or they can ruin the casting in a hurry.
Ironyetty, where are you located?

[ironyetty]

I trust that the guy who rebuit the carb did it correct, he was highly recommended. I am also going to recheck my timing and points gap. I am located in fort ashby ,WV.

[JD440ICD2006]

The bottom line is that if you are having trouble with the carb, and all other factors are correct such as timing, then it is not working like it should.
Aside from each carb needing to be tweaked differently, there is really no gray area on them.
If he removed the jets and cleaned as I said earlier, your problem is somewhere other than the carb.
Keep us posted, it is always great to hear when someone gets one running properly again.

[H-D]

Have you verified that the centrifugal advance is working properly? This is often misdiagnosed as a carburetor problem.

[Tigerhaze]

Hi IronYetty-

I guess I am a little confused as to what problems/symptoms you are still experiencing. My understanding from the initial post was that you had fuel overflow from the carb, which seemed to clearly be a carb problem. It appears like it now runs but is just idling rough? As others have mentioned, poor electrical components can appear like carb misadjustments and can make the carb impossible to tune.

Again I am drawing on experience with my Ford 8N tractor that has a M-S carb, but issues on that tractor that appeared to be carb problems (rough idle, missing, etc) could actually be worn ignition coil and worn points/condensor as you mention. However they could also be due to worn spark plug and coil wires, fuel fouled spark plugs, worn distributor cap/rotor, and other distributor internals (not only the mechanical advance sticking but also the secondary electrical wire and terminal from the coil to the points in the base of the distributor). Distributor timing adjustment shouldn't be an issue unless you had removed or unbolted the distributor recently.

[ironyetty]

Thanks for all the help, but here is the latest.

Engine is new rebuilt I mean everything, new distributor, new guts, newplugs, rebuild kit in carb, bored .040" over, machined head and engine block, rebuilt governor .......

So I had problems with float filling with gas, I got another float thought I had fixed the problem of the carb overflowing , not so. So I have just ordered a new replacement zenith carb that should be here next day. Obviously I skipped a few steps like taking the carb off and on about 100 times adjusting needles, recleaning, and bending float to compensate. I wish some you guys lived near by to help. I am hopeing the new carb will alleviate all the problems.
I am thinking a combination of several things on the old carb is causing me to slightly lose my mind by not being able to adjust the fuel.
I will keep everyone posted after I install the new carb.

[Swawpy]

ironyetty- I have been following along and hope you got your machine all dialed in. If all is well...are you interested in selling your old carb? I will send pm. Thanks