Mornin Jim, That 3/4 turn out for the load needle is about right, I start them at 3/4 to 1 turn out then fine tune from there. What's confusing is you mention you get a lot of black smoke, but thats caused from TOO MUCH gas, not too little which you need choke to make her run??
Black smoke can be from needles set too rich (open),, or too much choke,, or an air inlet restriction,, too high float levels,, etc. Let's start with some basic adjustments and troubleshooting: FUEL FLOW TO KEEP CARBS BOWL FULL 1) If you open the carb bowls lower drain cock/plug, do you get a continuous steady stream of gas about 1/16 inch in diameter????? ?? If so, flow in and out and through the sediment bowl and carbs inlet strainer and needle valve and seat are satisfactory. You might want to insure the lil vent in the top of the carb is open to allow air to exit the bowl when gas enters as it should, cuz if its plugged, gas cant flow and fill the bowl properly. 2) If gas dont flow continous out the lower drain cock/plug, take the line off where it enters the carb and insure a steady stream of gas the size of the lines inside diameter. 3) If not, remove the glass sediment bowl and insure the lil top holes are flowing gas well to fill the glass bowl. 4) If not, there is a restriction (rust or crud) up inside the inlet pipe or mesh screen if it has one. 5) If you have good gas flow to the carbs inlet connection, BUT NOT out the bowls bottom drain cock/plug, theres a restriction in the inlet strainer or needle valve and seat. You can first remove the lil side plug in the inlet strainer and try and drain and blow out any rust or crud and if that dont help, remove the top nut and round cap and blow and clean out the circular inlet strainer using compressed air and carb cleaner etc. and see if that causes good flow out the bottom bowl. If not, you might have to remove the bowl and remove and clean the needle valve and seat and check the float level to insure it shuts the gas off at approximately level. ONCE ALL FLOW TESTS PASS Once youre sure there's good gas flow filling the bowl and she still needs choke or black smokes, proceed as follows: 6) Assuming you have fresh clean water free gas in the first place, remove the air cleaners bowl and insure its not full of water and that the inlet pipe is not restricted. If so, that can cause the black smoke (too much gas) you described. 7) If she still needs choke to run despite needle adjustments and air inlet is free and all flow tests passed, theres either an internal carb blockage, float levels set way too low, maybe a bad vacuum leak, or the spark is weak. 8) Vacuum leaks suck in air which leans out the fuel mixture causing a need to use choke. Take Carb Cleaner or WD 40 or an unlit propane torch and spray around the carb (especially near the throttle shaft bushings) and manifold and base and see if she speeds up or smooths out. If so, you found the source of a vacuum leak which causes her to need choke to run. 9) If all flow tests pass and theres no vacuum leaks (assuming spark not weak, see below) there may well be an internal carb blockage. The first thing to try is remove the main center vertical brass nozzle and clean it and ALL its lil side holes. Restrictions there can lean out the mixture requirign choke. DO NOT pry down at its top up in the bore, you can crush or distort it. You may have to drill and tap its bottom center and use a screw and washers to pull it out then thoroughly clean and light wire brush it and all it lil side holes. Clean out all other passages and ports and then give her a try. 10) If its more an idle then under a load problem, you have to remove all the brass drill plugs (use heat just till color changes then let cool and remove) and use the extra long no 40 and 53 aircraft drill bits to clean out the passages behind them. See http://www.robertscarbrepair.com/tip1.htm
for a pic of those passages, and I use steel guitar sterings or welding wire etc to clean out the other smaller passages. IGNITION If all the above is good, a weak spark can be a problem. However, to save time and space, I will only cover a few basics now and you can post back if its a spark and not a gas problem for more detailed ignition troubleshooting. 11) Remove both plugs and with their wires attached and their sides up against frame ground, when you crank the tractor, be sure BOTH are producing a good visible blue spark NOT a faint thin wimpy yellow one. 12) If the spark is weak post back for more details, but in the mean time, check the points and replace them if burned or pitted or carboned up and insure the gap is 0.015 on high cam if its a Wico Mag. Just to be safe, I would try a fresh set of Autolite 3077 those side wire electrode plugs and see if she runs better. 13) Insure the rotor and cap is clean and residue free and has no cracks or carbon paths and you should have wire core NOT carbon auto suppressor plug wires. Let us know what you find and try and determine if its fuel or ignition related and we will go from there. If you dont get her running, I volunteer clooney to come fix it lol. Good Luck n God Bless the USA John T Nordhoff
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