TO 30 Carb Tuning Question Running Rich I think

Hoovey

New User
Hey guys - I've been getting some great info on here, thanks!!

I've been working on my 52 TO30 this winter. Done a few things to make it run better. Set timing, brought ground down to the starter, switched to Autolite 3116 plugs.

I took the carb off and cleaned it too. I checked the float (good) and replaced the main gaskets when I put it back on. Not too complicated.

I've adjusted the idle screw and main jet. I'm idling great after warm up. The problem is I'm backfiring a little, blowing too much smoke I think and I'm lacking consistent power. It's stalling on a load in higher gears like going up hill. I adjusted the idle screw first, then the main jet (big screw). I've have since tried to back off the main jet as much as possible without stalling. That's about where I'm at. I think I'm running rich and looking for advice.

Thanks,
Scott in MI
 
Backfiring is generally not from a rich condition. Sounds more to me like a lean miss. Not enough fuel in the cylinder does not properly burn
resulting in a mis-fire. Lean mis-fire.
Stalling go up hill.
Fuel level?
Pull the plug out of bottom of carb. Turn on fuel flow. Should look like 'cow pissin' on flat rock.'
No? Plugged filter, eh? Which one? Ya' got three of them.
As long as the plug is out of the bottom, insert brass barbed fitting. Place 18" clear hose over barbed fitting.
Hold open end of hose up towards fuel tank.
Fuel level inside the hose will match the fuel level inside the carb. Should be very near the carb center line housing gasket.
 

I did not unhook the hoses too carb yet but I did confirm a major suction coming from the intake on the dash. More gas more suction???

When I'm idling and I gas it quick it will stall. Still lot's of smoke??
 

I'm not sure what a cow pissing on a flat rock looks like. LOL.

I have pulled that plug on the bottom of the carb a few times and it sure seems like and adequate flow.

As I said up top it will idle great, right now cold it starts best with no choke. When it's idling and I gas it hard it will stall???
 
Smoke.
Color?
Have you gone through and checked/set the timing? Timing that is off can add to your problems.
Setting the timing is a PITA.
Me? I would statically align the timing mark at the specification given. 6 degrees BTDC?
Pop the dist cap and make sure your coming around to the #1 position on the cap.
Your not? Spin the engine around again and make sure the aiming the rotor at #1 inside the cap.
Got it? Good. Get yourself a flat bar, a 'C' clamp, a crayon or touch up paint. Secure the flat bar (I used a file) to the front axle
bolster. Get it about 1/8 to 1/4 inch away from the front pulley. Paint the end of the flat bar and a corresponding mark on the flywheel.
Start the engine, get to idle speed and check the paint marks with the timing light. ARE THEY ALIGNED? No? loosen the dist and move it
until the line up.
O'really auto parts might have a light to loan out.
They also sell the brass fitting to check the float level.
They might also have the clear hose while you are there. . .
 
Take a look at the ignition system first.

Check the distributor. The shaft needs to have very little side play. If the shaft moves, the points will not stay set. The gap can change under varying RPM, effect the timing, spark quality, and point life.

Check the centrifugal advance. The rotor should turn a few degrees CCW, then spring back when released. If it's frozen, sluggish to return, of moves without springing back, the distributor will need to be removed, disassembled, lubed, repaired... Or replaced with a rebuilt.

Also check the spark quality at the end of each plug wire. Should jump a minimum of 1/4" to ground.

This is important, the symptoms you describe can be a result of weak spark. You mention backfire, exhaust backfire is an indication of intermittent spark. Poor performance and carb backfire can be caused by retarded ignition timing (worn distributor, frozen advance).

Have the valves been set lately? They are probably OK being it idles well, but if noisy, or haven't been set in a while, might put them on the to do list. Be a good time to clean out the gas tank too.

On to the fuel system...

Has the air filter been serviced? Including the wire mesh inside the canister? It is often overlooked. It gets packed with dirt and has to be removed and cleaned or replaced. Not an easy job but necessary. It can also be restricted with mud dobber nests or mous nests. A trial run with the cleaner hose removed will tell the story.

The fuel supply. How is the tank? If it hasn't been cleaned or replaced, good chance it is getting grungy. The fuel flow test, try it again, this time get a clean glass ready, remove the carb drain plug, catch the flow. It will have a full flow at first, but let it continue to run. As the bowl empties out, the flow will slow, as only what is coming through the needle valve will now be flowing. That is the real test, you want to see a continued trickle, not slow to a drip or completely stop. If the flow is insufficient, try loosening the gas cap. If opening the cap doesn't help, start tracing the restriction back toward the tank. There should be a screen in the carb inlet elbow, a screen in the sediment bowl, and a screen inside the tank.

Look at what was caught. If the gas if cloudy or water on the bottom, or rust and grit in the glass, the same will be in the tank and the carb bowl. The tank will need to be removed, claened, or replaced if heavily rusted.

Once the fuel supply is good, the ignition system is right, everything else is up to par, then the carb can be adjusted. The carb will only work as well as the rest of the engine. A sick engine will not operate properly on any carburetor!

All adjustments need to be made with the engine up to operating temp with a thermostat in place.

Sounds like you already have the idle adjusted. Just an FYI, the idle screw adjusts air flow, not fuel flow. Turning it in richens the mix, out leans it. The adjustment is minimal. The RPM must be down around 400-500 RPM or it will not be fully on the idle circuit.

To adjust the main jet, have the engine at idle speed. Turn the main in (lean) 1/4 turn. Open the throttle fully and suddenly, observe the response. If the engine revs without hesitation, turn the screw in another 1/4 turn, repeat the test. Keep doing so until the engine stumbles, then start backing the screw out 1/4 turn at a time. The goal is for crisp response without hesitation when the throttle is suddenly opened. A single puff of black smoke is acceptable.
 
Steve@advance has the right order of things to check but doesn't say why that is the way to do it. Your tractor idles well because the airflow through the carburetor is limited so the compression in the cylinders is low. It takes the least voltage at the spark plug to jump the gap and make the fuel ignite. When you open the throttle or the governor opens it like under load, the throttle plate moves out of the way and a much bigger amount of air-fuel mix will end up in the cylinder and be compressed. This takes a much higher voltage for the spark to jump the gap and sometimes you are not reaching that voltage with regularity. The first place to look is the points. They need to be clean and to make contact properly. I've seen them with a twist in the arm that only let them contact on the edge. They should contact in the center. From there you go to checking the distributor to make sure that wear isn't causing the problem.
 

Thanks for all the information and time spent lending a hand!!

Great information!! I'm going to work on it this afternoon.

Stay tuned...
 

Here is an update - Letting her cool down after working on it now. I'm pretty much were I was...

1st - Checked air flow. Everything looks good, screen clean good suction and after I started it I disconnected hose to get free air - no difference.

Next checked distributor - Points look good almost brand new - did rotor test (check) goes ccwise a little then springs back, cleaned it up a little, shaft is tight.

Next did gas flow test. Pulled the plug and let flow - after bowl surge [u:540eefc42e]the continues flow was was much more than a trickle but did slow down[/u:540eefc42e]. Gas looks very clean - checked it in a clear cup.

Next did spark check with a Champion D-21 at 1/4" inch gap. All plug wires passed with a good spark across. Then pulled all my plugs. They are brand new Autolite 3116. The two middle plugs were a little sooty. The two end ones were clean.

Checked timing again. Found TDC on cylinder one and confirmed rotor pointing at plug one. Set flywheel to 6 degrees by sight. No timing light but warmed up the engine and adjusted distributor cap back at forth at various rpm's to find what sounded best. Found stallish spots in both directions - Seems good were it's at.

Once again idling good. I tried for a long time to eliminate stalling while gasing it as it sits at idle. Could not find a spot using the main jet screw. I did go in both directions with the main jet screw where it would stall easier. It seems to be best at about 1 1/2 rotations open.

Smoke is white. Normally only seen when gassing it. Idles great but stalls while under load (if not planning for the load) or giving too much gas too quickly.

Next I was going to check/widen gap on the sooty plugs after it cools. Can't imagine that would make that much of a difference. And... while checking the distributor, under the cap I could only see the rotor on top of a black plastic plate. Maybe under it something is goofy??? It looks and seems good though.

Also I guess maybe something is wrong from cleaning the carb. There just doesn't seem like there is too much in there to go wrong.

I did have some problems getting the glass, gas bowl to stop leaking. It seem to have stopped. I checked the gas cap an it seems to be passing air. I also have loosened and removed the cap to assist in gas flow - no help???

Almost stumped...
 
Does a partial choke help with the load stalling?

If so, it's probably still too lean.

If backing the main jet out more doesn't help, look for a low float level or a partially clogged main jet.

A jet that gets clogged from sitting in evaporating ethanol gas will need to be scraped out with a tiny drill bit or a torch tip cleaned.
 
Have you tried pulling plug wires off one at a time to see if all four are working? Those two spark plugs that were clean are suspicious. Firing order correct?
 
Mine was doing something similar. Turned out to be the manifold gasket leaking. Too much air on clean plugs and sooty on the others. I adjusted too rich to overcompensate trying to get it to run better.
 
"The two middle plugs were a little sooty. The two end ones were clean. "

#1 and #4 running lean and #2 and #3 running rich would imply a manifold gasket leak, Tighten down the end bolts on the intake manifold and see if that helps. If the problem persists, I"d consider replacing the intake manifold gasket.

Next, get a timing light and make sure that the initial timing is correct and the advance is working smoothly and the advance curve is correct.

Is the plug firing a bluish-white hot spark?

Do you have the correct carb, the TSX 458 and are all the passages in the metering section clean? The TO-20 carb has a smaller venturi so the throat pressures are lower at TO-30"s high airflow, throwing off the calibration.
 

My newish start took a poop so I can't do squat right now. Theses starters suck!!. I think they are 6 volt and I am running 12. I think I'll try one from this site that says it's 12 volt.

Anyway, I rechecked spark and it looks good all the way around. Your thinking was the same as mine on why the ends were not sooty.

I did pull the carb again and cleaned it up like crazy including the main jet and it's small holes and the screen form the gas intake. It ran much better, no smoke or missing. It did still hick-up or stall when juicing it from idle. All plugs now look sooty. Then my start broke...

I will tighten manifold bolts and check carb. Carb looks original but who knows.

I would like to get this thing so it starts and runs reliably.... or get rid of it. Spending to much time working on it!!
 

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