Hello All, Thanks for the info. We'll try your suggestions next time we are up there. You all have a nice Easter weekend. Joe Giraud:D

Oldnuc, Today I attacked the D47U with vengence. The victory had to be mine. I took the carburetor off again and I drilled out 4 lead plugs and then I chased the 4 passages with a small drill bit. Very little came out but a little did. I then took some solder and torched it into small lead balls and lightly tapped them back into the openned holes. I put it all back together again. It still ran like crap but there was a little improvement. Full choke helped but the exhaust was black when it ran. When it got warm it started missing on one cylinder. Earlier it had a bright blue spark at each plug. The right cylinder had gone dead. In checking, I found the left spark plug wire was laying against the pony motor exhaust and the insullation had burned through and shorted the plug wire. I fixed the wire and I started the pony motor again. The pony motor was stumbling bad but it was firing poorly on both cylinders again. Carb adjustment didn't seem to have any affect on the performance, and eventually it would die. I figured with the black exhaust and no response to carb adjustments, the problem probably was in my Wico magneto now. I took the magneto off and removed the points. They had some oil on them and they were lightly pitted. I took an oil stone to them and freshened them up and then set them at 0.015". I assembled the works again and I started it up. Same thing, full choke to keep it running. But wait, as it warmed up, I had to shove the choke in to clean up the exhaust. Tweeking with the idle and main screws brought it to a healthy sound again. For the hell of it, I started up the main and then I went out and pushed a couple of stumps out of the ground. It sure does feel good to have it running proper again. Thank you for all of the suggestions. On Easter Sunday, I get to demolish a bunk house with the D4. It should be more fun than the grandkids' Easter egg hunt.

The plug wires must be solid copper wire and not carbon filament or carbon filament wire wound. NAPA stocks a solid core wire, ask for Packard 440 and they will know what you want. Also use a non resistor plug. The NGK AB-6 or acceptable substitute. This will improve the cold running performance.

Sounds like you might have the carb on the run finally. A black exhaust indicates a very rich mixture. Have you removed and cleaned out the pony fuel tank? Mine was half full of un identifiable "stuff" and the expected amount of rust. Avoid gas with alcohol like the plague. Use the 87 octane stuff as it will not eat the float or suck up water out of th air.

I couldn't wait for Easter Sunday to run the D4 through the bunk house, I did it this afternoon. Driving the D4 through the bunk house was as easy as stomping a shoe box flat with your foot. What and experience! The 800 square foot bunk house had three rooms and the first thing I did was to tear out the corners of the house. The next was to hook the walls with the blade and pull them out. Eventually the house was pushed off of it's cement foundation and then walls fell flat. The trussed roof actually held the weight of the D4 as I drove the D4 back and forth trying to collapse the roof. Eventually the roof settled flat on the ground too. I am sorry that I didn't get any photos of the Cat on top of the roof with out the roof caving in. I was afraid of the Cat turning turtle if one track broke through first and the rest of the cat would follow. I had my seat belt on. Thank goodness that the Cat has ROPS. I then bunched up the bunk house into a tight pile and lit it off with a match. One hell of a hot fire followed. Later I restarted the D4 to bunch up the fire again. This time the pony motor ran fine with the choke all of the way off. It has never ran this good in the 6 years that I have owned it. I was having so much fun that I did some stump pushing up until 8 PM tonight. That is right, it was dark 8 O'clock when I finally parked it in the barn. My D4's performance today makes me proud of it.