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post #11 of Old 11-19-2012
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Re: Yanmar YQM15 - hard starting

Originally Posted by junaido View Post
Is there any harm to spraying a little "Heet" fluid into the air intake of a Yanmar 3GM30F diesel for cold starts? Its taking longer and longer, 20-30 secs of total cranking spread over two attempts to start it in the cool damp winter of the Pacific NW. I am worried about raw water getting sucked into the engine with all this cranking, not to mention the stress on the starter and batteries. However, one quick spritz of HEET into the air intake and the thing starts on first crank (1-2 secs max). Its a miracle drug as far as I can tell. My only concern is , is it bad for the engine in any way to use this spray ?
Using 'ether' to start a small diesel has its risks as if the 'combustion' occurs at the exact timing of FULL up or 'dead center' piston stroke while the engine is a 'starter turn over speeds' ... you can bend/break a piston rod. because of the dynamics and inertia of the crankshaft isn't enough to move the piston 'through' the 'end stroke'.
Put a 'hair dryer' or 'electric heat gun' into the air intake is a better way to start and with less 'risk'; the HEAT applied will be more consistent with the requirements of 'starting up' the 'diesel cycle' ... VERY different from the "Otto cycle" of gasoline engines. The diesel cycle MUST develop the proper amount of HEAT at full (top) compression of the piston for the oil to 'fire', the heat gun will allow easier 'firing' because it adds to 'heating up' of the fuel done by the compression.

BTW ... dont open the raw water valve until AFTER the engine has fully started when 'hard starting' is expected.
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