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Buickgsman

Got the B12 running today! Need ideas..

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Buickgsman
So I got the B12 running today. Thanks to Zetor for providing the fuel tank and some info here on the fuel shutoff valves and some wiring help. I had rebuilt the carb last week and put everything together over the last few days. She fired right up and ran pretty good. I am getting a little oil smoke when I give it some throttle. One thing I dont have hooked up is the crankcase vent. Could that cause a little oil smoke at throttle up? Other than that it runs pretty good. I do need to replace the starter generator because one of the bearings is making a lot of noise. ANd it needs a battery but I figured I would get it running before I dumped any more money into it. I do have to say that it rides noticeably smoother than my Big Ten. Are there any B12 owners that can tell me if I have the correct intake elbow from the carb to the engine? The throttle lever rubs against the crankcase vent tube.




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Buickgsman
I have a feeling it is some oil. There is some black mixed in. No smoke at constant throttle however. The carb doesnt seem to leak, especially at shutdown like my Big Ten so I am happy with that. Its running just rich enough where its not up and down on the governor. Its nice and smooth, but with a quick stinky oily black cough when throttled up. The engine hasnt been run in years so I am hoping maybe the rings free up a bit and the smike stops. Any chance the crankcase vent is contributing? Thanks!

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dentwizz
Make sure you get that hooked up eventually. It can allow debris to get sucked in past the air filter, but it does suck the oil fumes a bit better than the earlier free breathing design that the 23D had. I think that was the main reason(emissions), but when my two that have that design carb/pcv had that rigged vs unrigged the rigged versions smelled a lot less "oily".

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jasper
I don't think it is related to the breather tube but you will want that attached to the carburetor for the previously stated reasons. I obviously have not looked at your engine so it is difficult to have a good diagnoses....however based on your description of "but with a quick stinky oily black cough when throttled up" I would say the idle circuit is to rich or the main jet/emulsion tube is leaking. At an idle, if the engine is to rich, fuel will run down the inside of the carburetor and puddle in the bottom. When you advance the throttle and rapidly increase the air flow it will consume that fuel and cause an excessively rich mixture and the "cough" of black smoke. Some excess is okay because it acts to enrich the mixture upon advancing the throttle.(accelerator pump) but to much will cause a multitude of problems. (ring wash, stumbling, fouled spark plug, carbon build up in the cylinder etc.) If it is the idle circuit that is to rich it will take a minute or two of idling before it will cough on throttle advance, because it is consuming most of the fuel from the idle circuit. If the emulsion tube doesn't seal the fuel bowl it will cause the same symptoms (but with a quick stinky oily black cough when throttled up) however if it is the emulsion tube it will cough after a very short idling period (one or two second depending on the size of the leak)and the carburetor will continue to leak and drip on the floor all night as if the float were stuck. Al Eden covered this is in a previous discussion but it is over looked often on a two piece flo-jet overhaul. I can't count how many times I see this problem and it's associated missed diagnoses of a leaky needle and the poor repair of a fuel shut of being installed. This only works until the owner forgets to turn the fuel off and in turn alleviates the mechanic of any responsibility when he says "well it is all your fault, you forgot to shut the fuel off!" As a rule black smoke is fuel and white smoke is oil. Hope this is of some help Bob

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