One more time!
Greetings to all! Hope you've been having happy holidays! You may recall that a while back I posted about my MS TSX 706 on my 57 850 and questions about the seats etc. I have been working on this carb off and on since. I have been able to adjust the carb so that it runs fairly smoothly, smokes black smoke only upon acceleration then only light smoke, not much, but you know its there. The tractor runs fairly well, but when I pull the plugs they are sooted up pretty bad. Not oily, but black soot. As a reminder the engine has been rebuilt to include a valve job. Carb rebuilt too. I installed a Petronix ignition kit and Flame Thrower coil. Obtained immediate start up, which in reality was only marginally better that when stock. My rational was that a hotter spark would burn the fuel more completely. It may have, but the plugs were still black with soot. Yes, they were cleaned before the electronic ignition was installed. In searching for answers I found what is called Colortune which enables you to see the combustion as it happens. It is a spark plug device with a glass insert through the plug. Following the directions, when a carb is adjusted correctly you should see blue flame. I see blue flame while at idle. However upon acceleration the flame turns yellow which indicates too much fuel. Yellow flame is expected initially but is supposed to change to blue if the carb is adjusted properly. I was not able to achieve a blue flame at higher rpms. I checked all the recommended areas suggested by the manufacturer, no vacuum leaks. I contacted the Colortune company and they could only suggest the main jet was too large. I am going to take the carb apart again and examine each part. One thing have noticed is that the float spring from the rebuilt kit is different than the original. The original used a small coil spring, the rebuilt kit uses the type that clips on to the needle. I am considering putting all the old parts back in to see how that works. I am running out of ideas and am now thinking the carb is just no good and need to buy a new one. One thing I have considered is the precision by which the MS carb operates. I do not think it is that precise and perhaps I am expecting too much from it and that it will never produce a yellow flame at high rpm. I am looking for any suggestions. I have looked at the Zenith carbs and understand many are very happy with them, but rebuilt kits are also non-existent. Any feedback on the Zenith carb would be appreciated. I want to thank again all those who tried to help previously and perhaps have thought of something new. I apologize for the long post. Hope you have a wonderful week. Thank you in advance.
Greetings to all! Hope you've been having happy holidays! You may recall that a while back I posted about my MS TSX 706 on my 57 850 and questions about the seats etc. I have been working on this carb off and on since. I have been able to adjust the carb so that it runs fairly smoothly, smokes black smoke only upon acceleration then only light smoke, not much, but you know its there. The tractor runs fairly well, but when I pull the plugs they are sooted up pretty bad. Not oily, but black soot. As a reminder the engine has been rebuilt to include a valve job. Carb rebuilt too. I installed a Petronix ignition kit and Flame Thrower coil. Obtained immediate start up, which in reality was only marginally better that when stock. My rational was that a hotter spark would burn the fuel more completely. It may have, but the plugs were still black with soot. Yes, they were cleaned before the electronic ignition was installed. In searching for answers I found what is called Colortune which enables you to see the combustion as it happens. It is a spark plug device with a glass insert through the plug. Following the directions, when a carb is adjusted correctly you should see blue flame. I see blue flame while at idle. However upon acceleration the flame turns yellow which indicates too much fuel. Yellow flame is expected initially but is supposed to change to blue if the carb is adjusted properly. I was not able to achieve a blue flame at higher rpms. I checked all the recommended areas suggested by the manufacturer, no vacuum leaks. I contacted the Colortune company and they could only suggest the main jet was too large. I am going to take the carb apart again and examine each part. One thing have noticed is that the float spring from the rebuilt kit is different than the original. The original used a small coil spring, the rebuilt kit uses the type that clips on to the needle. I am considering putting all the old parts back in to see how that works. I am running out of ideas and am now thinking the carb is just no good and need to buy a new one. One thing I have considered is the precision by which the MS carb operates. I do not think it is that precise and perhaps I am expecting too much from it and that it will never produce a yellow flame at high rpm. I am looking for any suggestions. I have looked at the Zenith carbs and understand many are very happy with them, but rebuilt kits are also non-existent. Any feedback on the Zenith carb would be appreciated. I want to thank again all those who tried to help previously and perhaps have thought of something new. I apologize for the long post. Hope you have a wonderful week. Thank you in advance.