Sami: This sounds like worn valve guides and is not uncommon in horizontal
engines. Some of  the oil that stays in the cylinder head valve train area
after shut off finds it way through the valve guide and thence is
combusted. Not to worry too much as this not abnormal on moderate to  high
mileage engines. If it were more whitish smoke, I would be more inclined
to say that it was uncombusted fuel and condensation which dissipates
after start up. DC

Sami Dakhlia writes:
> 
> The 75 Bus makes a big puff of black smoke (almost?) every time I start
> it. The smoke dissipates after a few seconds and then things seem fine.
> Could it be worn rings? Can I afford to ignore the problem?
> 
> TIA for your input!
> 
> Sami
> dakhlia@wuecona.wustl.edu
> 

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David Carment
School of International Affairs
Carleton University
Ottawa, Ontario
K1S 5B6
voice - (613) 788-2600-6662
fax - (613) 788-2889
Email address: dcarment@ccs.carleton.ca
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