Carbs and black smoke Options

[pistonboy]

Hello

I moved a complete set of 44IDF carbs (complete with linkage and manifolds) from a 1.91 liter engine to a 2.73 liter engine. On the new and larger engine, black carbon is coming out the back. But it is not smoke. It is in the form of "soot" particles. Some are small and some are larger. I thought the jets were the wrong size but these carbs were producing clean exhaust on the smaller engine. If the jets were the wrong size, then there would be smoke, not soot.

The exhaust for the larger engine is a different system from the smaller engine. It is a used quad tip (Monza or Manta?).

Is it possible the soot is really carbon breaking loose from the interior of the exhaust system and has nothing to do with the engine? If it were the engine or carbs, it would be smoke, not soot.

What do you think? Has anyone had something like this happen with an old exhaust system?

Thank you.

[VaccaRabite]

You have gained almost a liter of displacement. You are going to need to completely re-jet the carbs if they were running "right" on your 1.9.

And the carbs have probably nothing to do with the carbon you are seeing. I'm guessing your used exhaust is blowing carbon soaked rust out the tail pipe.

BTW, don't run a 2.7 engine on a Monza exhaust - they are the worst of the readily available mufflers.. That engine NEEDS more flow. You spent the money on a big engine, you need to spend the money on a decent exhaust to support it.

Zach